I think Grindclock is too slow. After ten turns the most amount of cards you can mill is only 25 cards and while that is definitely worth the two mana investment, most times you won't get it out on turn two or you won't be alive (or your opponent won't be alive) and that's not barring the fact to get maximum usage out of it you need to play it early. Drawing it in the late-game is pretty bad.

I'd rather run Mesmeric Orb than it but I don't think I can afford to even do that (although I still kinda wanna add it).

Overall I really like grindclock (I used to run it in this weird fun deck I used to play) but it's not worth it in this deck.

Duskmantle Guildmage + Mindcrank = win forever

I've been testing this deck in Magic Workstation and I've been loving it. I've ended up winning all but a few matches with it. One of the notable losses was to a deck that sided in Leyline of Sanctity. I'm not sure if there are any enchantment hate cards in b/u but if there is I would consider putting it in the side, if that happens then I'd cut two of the Leyline of the Voids.

Awesome I'm glad you like the deck and I'm happy to hear it's been doing well. I have never run into Leyline of Sanctity although I know it does see play in a decent amount of sideboards. I honestly do not know how I would beat it and I don't think there is anything I could even side in to stop it. I could run some bounce spells and hope to counter it when they cast it again but that's about it. Maybe Cryptic Command in the sideboard? I can bounce it to their hand and assuming I have another Cryptic Command or some other counterspell then I can counter it when they play it again.

Anyway thanks for the feedback!

One idea I had for dealing with Leyline of Sanctity is try to find to splash white by attempting to squeeze in a couple Godless Shrine or Arcane Sanctum and have either Esper Charm or Mortify in the sideboard.

If your opponent sides in Leyline of Sanctity, side in Hunted Horror and they won't get the tokens, and you could also side in Jace's Phantasm and mill yourself and just be super aggressive with the horror and phantasm.

Really like this, +1

Not sure if you'd try it, but I've got a similar deck in Esper colours. Gives me Path to Exile and access to Ghostly Prison which is great against aggro and all sorts of decks--Affinity, Zoo, etc...

Not sure you'd want to change your manabase however. Also experimenting with Spreading Seas and the new card Fraying Sanity which might be worth a look.

Nice list!