Firstly I want to say I LOVE YOU TURBINE!
What's the deal with spell criticals?? When your wall of fire criticals, the whole thing is doing critical damage thru its entire duration... BUT if you shoot frost lance, one of them may critical and the rest do normal damage... What's the deal with this? AoE spells are obviously either critical or not critical... why can't they be rolled per hit, not per cast? Doesn't that make more sense?
I can imagine this is a tough fix... But in my humble opinion, it's one of the most important things to be fixed.