Arkaj

Replace Rupture Spire with Dimir Guildgate.

I like your idea, and this deck could become slightly more competitive if you do two things.
a) Add some more two mana creatures. Gates enter the battle field tapped, so your two mana creatures will enter the battlefield a turn late. Aside from that, you have few of them, and you mana curve is a little broken.
b) You need some mana fixes so you can actually play your cards. I recommend, Realmwright. He is a one mana blue creature that turns all your lands into a basic land in addition to their effects.