This deck is giving me such a nostalgia trip, it's really similar to my first EDH deck. I went a little heavier on the enchantment theme though, like including Enchanted Evening so that I could sac anything to Ertai or steal everything on the board with Aura Thief.

There are cards in the deck that I think you could take out for Elesh and the Wurm, but the issue I'm having on my end is that it looks like you've filled the deck with a bunch of cards that you just find fun to play with. The Dovescape + Guile is the heart of your deck, but what else do you want to make sure stays in?

Is there a chance you could give a rough estimate on the sort of budget you are interested in putting towards this deck? It would help me focus any suggestions I might have.

SaberTech, thank you for taking the time.

Concerning budget, I rarely justify spending more than $15 on a card. For example, Academy Rector is an exception here.

As this is a concept still, that I'd like to flesh out somewhere in the coming months after playtesting with proxies, there's very few must haves. Dovescape and Guile as well as most of the tutors, including the ones that look for lands. Other than those, Boseiju, Who Shelters All is the only other card I'd like to keep, which is the reason I'm going heavier on instants and sorceries. Oh, maybe Supreme Verdict as well for it being the perfect answer when I need it.

That is all, so feel free to fire away any and all suggestions you may have! I wouldn't mind taking the deck through a series of revisions to make it as pleasant to pilot as possible. Already considering Enchanted Evening, it looks amazing!

On a last note, I play in a casually competitive environment, if that makes sense. Winning is not everything, but we don't shy away from anything that's interactive and promotes the game without stalling/creating chaos unnecessarily.

Ok, so looking at your list there are two aspects that jump out at me as being possible issues with how the deck plays:

1) A restricted pool of efficient mana ramp options in combination with a bunch of the really cool spells being 5+ mana to cast. This is a general issue with playing esper colours unless you have access to money cards like Mana Vault, Mana Crypt, Mox Diamond, etc. You are already running a number of the cheaper options, but it might also be worth looking at Coalition Relic. It's pushing your card price limit, but the mana ramp and fixing that it offers is great, especially since you are running a few cards that cost three of a particular colour of mana. Some other ramp options are the myr creatures like Silver Myr. They are vulnerable to creature removal, but they can also be sac-fodder to Ertai if you draw them when you don't need them.

You can also look at trimming down your mana curve a bit so that you're not as reliant on mana ramp to be active early in the game. Your morph creatures don't have synergy with other parts of your deck, which means that with Voidmage Apprentice you are investing 7 mana to counter a spell. Sure, after it flips you can sac it, but that means an additional mana and getting Ertai on the board just for the payoff of countering two spells. I think that there are better ways to invest your mana.

Other cards to consider cutting are Lost Auramancers (likely to be killed before losing all its counters), Planar Bridge (again, likely to be destroyed before you can use it), and Ethersworn Adjudicator (I've tried it, and it either dies quick or demands too much mana to use when you have other cards you want to cast). Docent of Perfection  ^Flip is neat, but its ability being spell reliant can be an issue, so how about Bloodline Keeper  ^Flip instead?

You have also opted for a selection of expensive to cast counterspells, which would probably be more effective if you found cheaper alternatives instead. Ertai should be carrying a lot of the counter power, so other counterspells in the deck should be aimed at either helping to protect him or helping to make sure your big spells to slip past enemy counterspells. Either way, it's better if they are cheaper. Speaking of Ertai...

2) Ertai could use a bit more support for him to make him more effective. Thousand-Year Elixir is a good option, and gets better the more creature you have that tap to do something. Lightning Greaves is a must have for the protection and ability speed that it offers. And a monetarily expensive option, but useful, is Spellskite. It can draw away spot removal or be sacrificed to counter a wrath.

Regarding sac fodder, Bloodghast is a great option that helps offer redundancy alongside Reassembling Skeleton. Bitterblossom is an option, but you could prioritize getting Kjeldoran Outpost and/or Moorland Haunt since they cost less money and are searchable with Weathered Wayfarer. To go along with the additional token generation, Skullclamp gives you a card drawing engine.

Sorry that this comment has become so long. I'll leave it at that for now. There are a few other ideas I could offer, but it would be better to wait until you decide which way you would like to go with the deck. Anyway, I hope I've given you a few ideas to work with.

Thank you for all the suggestions! I will work with those in mind, next time I find some time! :)

I'd welcome any further discussion once I finish the first major revision.

Ascendant Evincar and Night of Souls' Betrayal help make sure your opponents can't keep their birds or other small creatures. Though you may want to add some one sided +/+ effects if you use those. Jace, Unraveler of Secrets ult is slow to get to but works great with Guile, Nullstone Gargoyle also great with guile. Rule of Law is a solid way to lock a game down with unraveler or a partial lock with some of the other things.

I really like Jace as he can provide card advantage and get me ahead tempo-wise. His ult is just gravy. The gargoyle won't be doing much once Dovescape is out, so I think that card doesn't fit what i want to do at that mana cost.

I have considered the Evincar and the Night amongst a million others (with Illness in the Ranks being the most prevalent), but I think the need for a few extra slots reserved for anthem effects is going to hurt the way the deck functions. I'd have to remove tutors or card draw or removal for cards that provide little synergy overall. I think Elesh is enough for this effect, while Massacre Wurm can be a big blowout.

I tested your deck a bit to see how it plays out, and just wanted to share some observations.

With the ramp you've included, the deck seems to be pretty consistent in hitting the 6 mana mark that you need. It comes at a bit of a cost though; spending your first few turns ramping means that you aren't playing cards early for Ertai to work with. I almost never wanted to cast Ertai when I hit the 5-6 mana mark because my board position was never at a state to take advantage of him. With the way the deck is currently designed, I think that what you need to do is include more wrath effects. That way, you can spend the first few turns ramping, then wipe the board, and afterwards play Ertai to hold back anything really threatening while you try to go for your end game. Wrath of God, Day of Judgment, Martial Coup, and bringing back Cyclonic Rift are all worth considering. I would also consider bringing back Reassembling Skeleton because of how it can block early and come back after a wrath to fuel both Ertai and Skullclamp.

Your selection of counterspells could be modified a bit. The ones you have are cheap and good for protecting, but not effective at helping you deal with opponents' counterspells. You currently have no way of getting Dovescape back if it is countered or destroyed by a creature. You could exchange Hindering Light for Negate and Turn Aside for Counterspell. I like the Rebuff the Wicked though, since it lets you leave blue mana up for other things and because no one expects a counter to come if you just leave white mana up. Open the Vaults or Auramancer might be worth including as a way to get Dovescape back if it does hit the bin.

Cards that under-performed for me were: Athreos, God of Passage (there weren't many threatening creatures on my board for it to matter); Kor Cartographer (there is enough cheaper ramp in the deck that I usually wished I drew a different card); Expedition Map (never wanted it considering all the other ramp and land search that is in the deck); Diabolic Intent (I only occasionally had a creature in the early game to sac to it); Skeletal Scrying (never had that many cards in my graveyard early on, and it was usually easier for me to search up Necropotence); and Utter End (expensive to cast and usually left me wishing it was a Swords to Plowshares or Cyclonic Rift).

You were right about that Netherborn Phalanx though, it's a nifty bit of tech in this deck.

Hmm... I actually like Expedition Map as it can look for Boseiju. Hindering light is also appealing to me since it replaces itself. I do see your point for more wraths as well as good reason for the skeleton (I don't know why I left that one out to be honest).

I think I misunderstood Skeletal Scrying... I have to pay the X in both mana and cards? Shameful! I'll replace it immediately with a better draw spell!

A little bit surprised about Athreos, but in retrospect it provides very little to the deck. I'll think on a replacement as well.

Concerning Auramancer's effect, would Hanna, Ship's Navigator be better or worse in your opinion? I like that her ability is repeatable and extends to artifacts, but that may be too slow/expensive (if an elixir happens to be around). On the other hand, Auramancer is just a one time thing, it's more narrow, but you get it immediately. I am a little torn... Ebbing towards Hanna atm.

Hatching Plans looks devilishly synergistic!

There's an argument to be made for using Hanna in your deck, since she interacts with cards like Thousand-Year Elixir and Pemmin's Aura to give you lots of potential long term advantage. She also plays nice with Seal of Cleansing. If you were to drop black and just go U/W, I would suggest either her or Grand Arbiter Augustin IV to be your commander. That being said, to get her effect you have to usually wait until your next turn. That gives your opponents a heads up about your plans and a chance to disrupt. Your other enchantments are worth getting back if they do get destroyed or sacrificed, but considering how few of them you have in the deck you may find that Hanna spends a lot of time sitting on the board doing very little. I'd give her a lot more consideration if you were going heavier on the enchantment theme and were running cards like Sigil of the Empty Throne and Hatching Plans (I typed this up before seeing your latest comment, thankfully I saw the new post in time to edit).

My argument for Auramancer is just that it does what you need it to do as soon as it enters the battlefield, and then leaves a body behind to sac to Ertai to help make sure that Dovescape gets another chance to hit the board. You could do it all in one turn if you had 10 mana, although it would require a lot of white and blue mana to pull off.

I'd also like to re-suggest Bloodline Keeper  ^Flip over Emeria Angel if you get your hands on one, since it works that much better with the inclusion of Thousand-Year Elixir and Lightning Greaves on top of Pemmin's Aura.

I'll give Hanna a go and see how much value (or lack thereof) I can get out of her.

You make a compelling argument for the Keeper. I will replace him.

Moving on to proxy-ing the cards I don't have (which is a lot :p ) and taking it for a couple of spins with my playgroup!

Thank you guys for helping me! I'll be making updates after i've got a couple of games under my belt!

Keep your suggestions coming, if any! I'll consider them all!

I'm subscribed to your deck, so if you ever want me to take another look and offer suggestions just drop a comment and I'll see it.

I had forgotten that Hanna can also bring back Spellskite, which is another compelling reason to run her.

Oh, and I forgot to mention that a lot of your mana base comes into play tapped. I didn't find it as bad as I thought it would be thanks to all the artifact mana ramp, but there were definitely times where I drew a tapped land on turn 5-6 and it set my play back by a turn. It's worth keeping track of in your games to see how big an issue it turns out to be for you.

Lullmage Mentor synergizes very well with Ertai, the Corrupted: every time you counter a spell with Ertai (or without him) the Mentor will create a token and thus give you more sac-fodder for Ertai. Also Reef Worm might be worth looking into as it gets bigger every time after you have used it to counter a spell with Ertai, the Corrupted

Thornbite Staff will auto-untap Ertai, the Corrupted because it triggers every time you sac a creature when you use Ertai's ability to counter a spell.

Martyr's Bond or Grave Pact will force your opponents to sacrifice their stuff too whenever you activate Ertai, the Corrupted's ability. As both the Bond and the Pact are enchantments themselves they can also be sacrificed to Ertai, the Corrupted if in times of need.

It has been quite some time since I started playtesting with the deck but I'm still gathering game info. Tomahawk-Barang, thank you for the suggestions. I have seen that the untapping enchantments can tax my blue mana heavily, as such, i'm taking Freed from the Real out and will try Thornbite Staff instead. I understand it's more expensive, but it costs 0 blue, meaning up to 4 more activations from Ertai.

Really liking how it performs so far! :D

Tomahawk-Bang... sry for getting the name wrong! T_T

But credit given to where credit is due! Thank you!

This deck looks really fun and full of great synergies.

Why are you running the artifact lands?

Sun Titan might deserve a spot for Ertai fodder retrieval.

Cut one of the sorcery draw and add Rhystic Study.

Guile is also really mean with Decree of Silence.

Ophiomancer is really mean with Contamination.

Perplex and Muddle the Mixture are counters that also tutor for big pieces in your deck.

Hello SufferFromEDHD and thank you for the comment!

It is as you said, this deck has been performing really well for me :)

The artifact lands are there to feed Thopter Spy Network in the off-chance no other artifact happens to be around.

The two counterspells you mentioned, are definetely good cards, but at those costs there is enough redundancy in the deck to make cheaper countermagic more preferable over the tutoring.

Rhystic Study is a mighty fine card, but in my playgroup it would draw me far fewer cards than you'd expect! It used to be in the deck and I took it out to better streamline my draws.

The Titan I'd considered getting him in, but couldn't find enough space. Hanna, Ship's Navigator is currently one of the golden pieces in the deck, and I know the Titan would work wonders as well, but I can't see what cut I'd make for him.

Now, the decree and contamination, are pieces I definitely would have liked to get in there (Solemnity too for the hard lock) but I opted not to, because I didn't want the deck to be as disgusting as it potentially could be. I do have them at the ready for any tournaments I may join though ;)