Just for my own edification;

Swapping out
Psychic Membrane for Wall of Denial
Arctic Aven for Daxos of Meletis
Pin to the Earth for Library of Leng
Tower Drake for Gwafa Hazid, Profiteer
a Island for Tamiyo, the Moon Sage
Paraselene for Venser's Journal
Hands of Binding for Spellbook
Feeling of Dread for Graceful Adept
and Last Thoughts for Grand Arbiter Augustin IV

Where to start... so many staples... BTW PLS READ THE WHOLE THING!!! IT WON'T LET ME PUT ALL THE SUGGESTED CARDS TO YOU! IT ONLY SHOWS SO MANY I CAN TICK IN THE BOX!! YOU WILL HAVE TO GO IN AND LOOK AT ALL THE CARDS AND PUT THEM TO YOUR MAYBEBOARD MANUALLY

Ramp, you kinda have the right idea for Ephara. You need some smaller creatures to get your early card draw and ramping goin. That being said, you have to many, and you also a lot of useless things. You need mana rocks, and you need bombs... not a bunch of useless creatures that do nothing in EDH. EDH is not like standard where casting a target spell at one opponent is good. Group hate cards > single target.

You are playing U/W but you have no bounce, no sweepers? That's a mistake on so many levels. EDH gets out of hand quick, so you need control aspects regardless of what you are doing. Your deck needs to be resilient, and this deck is far from.

You really need bigger bombs... none of your creatures screams... OOH BOY I'M A BOARD CHANGER! I STAY AROUND AND I'M GONNA FUCK SHIT UP!!!

......................................................

So with that let's start with some cards to get in here, and we will start with ramp!

Sol Ring is a must in every deck. 1 mana for 2? Come on now

Nykthos, Shrine to Nyx

Ancient Tomb

Gold Myr + Silver Myr are both low drops that help you get out your general faster, as well as give you cheap body that helps you draw incase you don't get them early. It's still mana to help you pump out other spells as well.

Azorius Signet Helps you filter out your mana, and still gives ramp. Turn 1 play land, sol ring, signet. Damn.. turn 2 general... that's hot! This is how EDH is won. Advantages that add up and get you out earlier than your opponents.

Gilded Lotus is nice for mid/late game. 3 colored mana to keep up especially when you get cards like Brago in here.

Thran Dynamo Cause Urza had some good inventions... let's honor him by playing them.

......................................................

KK now creatures! This is your bread and butter, your recipe for success, and a huge draw engine for you.

Brago, King Eternal helps you proc your general ability to draw, also blinks all perms. You tap a mana rock, creatures that attacked or tapped for an ability, enchantments you might have tapped, etc. Now it's untapped to be used again (if has haste or incase of manarocks can tap to play more stuff, or hold up counter magic.)

Brimaz, King of Oreskos Guy is a champ in here. Card draw proc, and just good 3 mana 3/4.

Hero of Bladehold Same as above, gets you cards, and she's just a good body to help build up your advantage.

Karmic Guide Graveyard recursion is good, and you need some playing white. This guy is a staple in white as is the next guy, infact they combo well together and have good synergy.

Reveillark Get your 2 creatures back for evoking him, or playing him and chump blocking? Why not, it's a lot of card advantage.

Sun Titan See this is what you want right here. A nice beefy 6/6 that gets you shit back from the grave when he enters the battlefield, or when he attacks. This is good shit right here. He's a white card staple, and puts in a lot of work in your deck.

Trinket Mage This right here is a bread and butter of blue cards. Gets you a sol ring, or a Sensei's Divining Top, or a Skullclamp. You play it, you get card draw, then you also get to tutor... what's not to like?

Phyrexian Metamorph clones are op as shit in EDH, especially when they can clone multiple things and not just creatures. Your opponent has that really nice artifact... now you do too! Thank him for sharing that wealth!

Restoration Angel This card right here... a 3/4 flier that bounces shit... what? So good!! ETB effects are what Ephara is all about, but this is better then cloudshift. It's a body that blinks.

Elesh Norn, Grand Cenobite Hey Hiroshima called... they wanted their bomb back. Cause that's exactly is what this is gonna do. They will look at this and be like.. wow.... I wish I was good at the game.. especially when you played Brimaz and Bladehold and have a few tokens that get pumped out that are bigger now. Also your big stuff is now bigger.. ooh right did I mention their shit is weak? You might even remove a couple of their cards from the table. That's a global 4/4 difference in creature strength.

Mother of Runes you are gonna need to protect your win cons.... and she is a tender loving mother who wants to see you win. She is like.. ooh no he's gonna cast that kill spell... ooh but don't worry child... I'll take care of this for you <333. I wish my mother loved me as much.....

Stonecloaker again more bounce, but you get graveyard hate as well. Don't want that pesky card coming back from their graveyard you guys just hated on. But now you can hate on it even better, while also bouncing a card you want back, and it's flash.. so you can even save a card from their hate.

Teferi, Mage of Zhalfir cause sometimes you wanna play solitaire. It's actually cause you don't want your opponents fucking with your shit, but it's ok, cause you can fuck with their shit. You are greedy like that! Your game, your win, their loss. Also you wanna flash shit in on their turn as well to deal with shit. A guy plays Gaddock Teeg and wants to stop you from playing your game... WTF?! AAAAAH HELL NO! You just flash that Elesh Norn in response.. see how he feels about that :D

Avacyn, Angel of Hope cause you need game winning bombs like this. Plus wraths are fun to play when you play her. Hahaha good times wipes tears of joy from eyes

Venser, Shaper Savant for those uncounterable spells. Bait them into playing supreme verdict... do it.. then go Yao Ming Meme face and say, "BITCH PLS hahaha" then return that shit to their hands and watch it fizzle. Then you bounce him so they can't play that shit again ahaha.. good times.

Consecrated Sphinx I can have all the cards you can have, and then more, cause that's fair!

Glen Elendra Archmage counter ALL THE THINGS.. then bounce her and replay her.

Clever Impersonator this guy is pretty clever alright...

......................................................

Board sweepers... these are a must. You are playing blue white, and you want to keep your opponents off your jock. Temp my good child tempo.

Wrath of God the godly staple of removal... literally

Cyclonic Rift this baby is the most one sided sweeper known to man. He's nice early game for 2 mana on that one card your opponent has, but late game.. he's nice for ALL THE THINGS!!!!

Evacuation this guy is a good friend of cyclonic rift.

Rout Wrath brought his instant speed friend

Day of Judgment Wrath brought his little brother.

Swords to Plowshares cause sometimes... your opponent has avacyn too and you don't want that bitch coming back. But yours is fine though... how dare he steal your ideas.

Path to Exile aww this bastard thinks he can play Elesh Norn too eh? or some other crazy beater or something. Yeah he can, but it ain't staying. He ain't paying you rent, so evict his ass.

Terminus cause.. ya know.... ya don't want that guy replaying shit you bounce.

Detention Sphere sometimes ya just want to remove something... and then bounce it abusing triggers permanently exiling their shit lol.

Oblivion Ring cause lol why not do the same thing 2 different times.

Austere Command for that artifact, enchantment, or creature hate all in one... sometimes choosing is hard man.

......................................................

Tutors and card draw are very important. Ephara needs help, and she shouldn't be your only draw engine.

Rhystic Study lol do you know how often people won't pay the 1? ALL THE TIME LOL.. so many cards drawn 3 mana gg.

Ponder cause you got decisions to think about

Brainstorm clutch plays

Fact or Fiction so goooooooood. Make them pull out their man cards and tell them to 5 and 0 you. Real men don't care about what you get. Pull that line on them... sometimes it works

Future Sight it's not card draw perse... but you can play that shit... which is like you drew it in your hand ... right?

Blue Sun's Zenith I have no idea who blue sun is, or why he has a zenith... or what one is... but hey nice guy to let us draw cards right?

Sphinx's Revelation wait.. we can have our cake... and shove it in our opponents face too? Sweet.

Sensei's Divining Top it's not cheating... no seriously it says guys I can look at the top 3... AND..... put them back how ever I want. God get good at the game like me.

Mystical Tutor cause ya want that counter on deck, or Rite of Replication

Enlightened Tutor Sometimes ya can't wait for things... that's ok he thought you wouldn't want to wait either.

Skullclamp for all those meh low drops that aren't useful to you any more. Card draw op

......................................................

So sometimes we gotta stop their game plan... COUNTERS!!!

Arcane Denial Tell him he can't play that, but here.. no hard feelings right? Then be like wait wait... if you are drawing. I'll draw double cause it's only fair right? How dare he be so rude.

Counterspell bread and butter... if bread and butter was more like steak and sauteed mushrooms and onions... and all the fixings.

Dissipate Cause Counterspell and swords had a child. Beautiful isn't she?

Pact of Negation sometimes... we just done goofed... it's ok he's got your back. But he will want his payment for helpin you as soon as you can..... also make sure you leave a notice to yourself... like a weight on top of your deck.. with a note saying.. PACT WANTS HIS MONEY!!!

Render Silent Some mages just don't shut up... but.. wait we are mages too... ooh right.. just cast that silencio spell we learned at hogworts on him.

Spell Crumple cause ya know... it's a gift that keeps on giving lol. You can't have it.. but don't worry I'll put it back in your deck safe and sound. <333 ooh but I get to as well cause ya know.. fair is fair.

Hinder cause ya know... you are a nice guy sometimes too

......................................................

Cards that will help you get more value out of ephara, and just your other creatures in general.

Crystal Shard cause you can target your own creatures for 1 blue.. and choose not to pay the 1.... god you are so fair and just to bounce your own stuff. Nice guy greg right here... but then replay it again.

Cloudstone Curio Sexy in all it's glory.

Rite of Replication while not a bounce... it will make your opponents bounce out of their seats when you copy something really good.

I've already stated a few bounces as well in this entire long post. So look through you will see a couple.

......................................................

You will also want to get a few things like Bribery in here or Hive Mind or what have you.

haha not hivemind, I meant Mind Control sorry about that.

but thinking back.. meh mind control isn't that great either.. where as bribery actually puts it into play so it's better.

I'm running this deck on an extremely limited budget, but I have taken in to account some of the suggestions you had... for instance, I love your idea of including Crystal Shard and I just so happened to have one... I also managed to trade around for an Isperia, Supreme Judge and a Nykthos, Shrine to Nyx. With those plus the cards I've still got coming for this deck (annotated in the first comment) I think this deck will wreak some excellent havoc ;) Just one thing tho, I did wind up pulling out Graceful Adept for Tower Drake just because with Tamiyo, the Moon Sage and Venser's Journal AND Library of Leng AND Spellbook not to MENTION Reliquary Tower I felt there was probably more I could do with a buffable flying blocker than another creature to give me no max hand size. As always, suggestions are welcome and encouraged. I don't think I would've thought to put Crystal Shard in there had you not suggested it and it could prove quite effective. (I'm thinking Lavinia of the Tenth) Also, in regards to your last note about Mind Control, I used to have that card in this deck back when it was a standard 60 card format, but this deck does so much tempo control I don't think I really need it (plus Daxos of Meletis .. hate? what?)

Np, that's why I throw in higher money staples, and also lower costing that makes a lot of impact. That being said, I still think your deck should have more over all synergy and a little more control, but that said... as long as you have fun that's what matters.

Also yeah I later said mind control was not a good choice, I was thinking it was like bribery and puts a creature into play, but I forgot it takes a creature in play already, so it won't draw you a card on your commander.

I am very surprised to see only one card in the whole deck that has the synergy with Ephara that makes a strong commander (AEtherling). What you need are more flickerers (Deadeye Navigator) and more token engines (Thraben Doomsayer). These will let you draw a card on each player's upkeep if you activate one each end step: MagicalHacker - Ephara, God of the Polis. My suggestion is to look at that deck and the staples on my profile and use them to build this deck into a machine. :)