Graveyard Edit!

Ages works as better reanimate target in dimir. Blue wants spells in graveyards as well
Dowser gives you payoffs for putting spells in graveyards just the same
Third path gives double prowess trigger, mills cards for reanimate/spells, and pays itself back eventually.
Express is too powerful. Holding is part of this new discard/mill package
Insight is a better Multi on 4 and can be played after milling. It can also be a late discard for reanimate.
Balmor is cool but didn't benefit from blue as much since it had fewer creatures. This card would probably be splashed more than anything else and would be confusing to players. --Gandalf's Sanction-- Enigma drake gives a much better signal as to what izzet wants to do.
Ashnod for counterplay
Flame Sweep is the sweeper I've been looking for. Your sprite dragon will live. Everything else dies.
Halo has the same problem as balmor to a lesser extent. Tainted gives more counterplay, discard target for reanimate!, and puts more spells in the yard.
Giving up rona is sad, but alchemy is just what the doctor ordered for this mill package. (Plus we introduced two new bounce spells)

delvers power slowly grows