Yea, the more I've played it the less I've used the draining whelk despite its interaction with the navigator. I've been playtesting against yours primarily. I'm finding that your ramp still beats the deck in general. I have found that with the variety of pieces I can go infinite rather early (I think the earliest so far was turn 4), if that happens I typically win since I can cast dralnu and easily win with something in my graveyard or cast a tutor for blue sun's zenith.

No Mercy might be something to consider. Punish opponents for attacking you. Seems like a solid deck overall!

Please give me some feedback on mine. Rakdos: Multiplayer Commander

instring chose of comander for U/B

Vendilion Clique is another win con with Tunnel Vision

You could use fateseal cards such as Spin into Myth to get cards that you know the name of onto the bottom of your opponent's library fast.

If you're running Basalt Monolith then you may want to consider running Mesmeric Orb and at least 1 card like Ulamog, the Infinite Gyre. If you play it right it'll potentially give you psuedo anti-graveyard hate. 1st main phase mill yourself untill you have something you can work with. go to combat step. second main phase, mill yourself until ulamog. No GY left to hate out.

Whilst on the topic of gy hate: You should run something like Leyline of the Void Just because you're running a gy centric deck does not mean you shouldn't have answers to other gy decks.

I won't suggest ramp until you figure out how you want to work your landbase.

Kira, Great Glass-Spinner should be highly considered to protect your combo pieces. It also protects against triggered abilities.

Make use of lands like Academy Ruins and Alchemist's Refuge

You have a tonne of triggered abilities. Consider Strionic Resonator

You may want to include a Maze of Ith since you lack meatshields. I'd also recommend Gravecrawler. Aside from being a recurring meatshield for 1 mana it can also be used in sac based combo's

Oh and I think there's a card that counters 0 cmc cards or "less than 1 cmc" at a cost of 0 cmc or life. Useful against carebear shit like Tormod's Crypt. Can't remember the name though

Pact of Negation

Hero's Downfall is a strict upgrade over Murder.

All-in-all, cool deck though!

Cool deck. Just quickly noticed that Murder could be cheaply upgraded with Hero's Downfall so you can hit planeswalkers as well if needed.

I know it's a weird thought but you could always run a Laboratory Maniac, so if you can't mill your opponent out you can always deck yourself for the win, just get the lightning greaves on him and counter a spell you own with hinder and follow that with a tunnel vision and draw a card or two next turn, if you go in that direction or find yourself going against another heavy mill or control deck then you could do that, alternatively if you find yourself in a tight spot then maybe casting an Psychic Spiral, I don't really know how they budget out though. I hope this was somewhat helpful.