I don't have too much to add: Doomed Necromancer seems pretty mediocre, as do Avatar of Discord, Call to Mind
Looks pretty tight though
I would say take out Exhume . Because the point of Thrax is to have your opponents sac their stuff, you're letting them choose the cool stuff that you've removed and put it back into play. Adding proliferation that does other stuff would be a cool interaction with your general also, so card:Tezzeret's Gambit, Volt Charge , Contagion Engine .