[Draggor]

It's mostly only rogues that have improved evasion. Spell focus will increase the dc of spells for a particular school. Dc's are based off your spell casting stat so increasing that will increase the dc too. Evasion only works against spells that allow a reflex save for half damage, so while fireball is out, flame strike will still do divine damage, ice storm has no save, and anything needing fotitude saves works well, so hit them with disintegrate, finger of death, wail of the banshee, implosion etc. Of course evasion also has no effect against a nice big sword/axe/mace/claw etc.