Commandeer is a great card for taking away an enemies planeswalker, or enchantment, or even a nice combocard that they really needed to pull off.
Frost Breath is the best answer I own for dealing with creature heavy decks and rush decks.
Trickbind and
Disallow are very nice cards indeed, one allowing (or disallowing more likely) you to counter a spell, or a planeswalker ulti, or even just a really annoying ETB, though
Trickbind is more suited to that,
Disallow works just as well.
Take Inventory and
Arcanis the Omnipotent are the card advantage, Arcanis has been one of my favorite cards for a long time and he sees very little action, unfortunatly. Take Inventory should speak for itself with card draw, it's basically
Accumulated Knowledge but modern legal.
Frozen Solid is a very nice anti-creature card, and its also creature removal if played right, what's not to like?
Imprisoned in the Moon now that is a card more tailored towards dealing with pesky planeswalkers or Indestructible creatures, or maybe even the only mountain your opponent has in a red heavy deck, the card is nearly ireplaceable.
Exhaustion oh boy, this card is a mean one. early game, tapping all of their lands for a turn get's pretty annoying, and if your creatures are tapped, it gets even worse. Now, as for the Jaces;
Jace Beleren and
Jace, Architect of Thought. Those are essentially the win conditions (though this deck wasn't made with one in mind). Architect's ulti is by far one of the best for any planeswalker, and Beleren is VERY nice card draw, and it even sizes down your opponents deck quite a bit in the long run.