Some suggestions on balancing ...
1. Sleet Storm - even if you MAKE your save, you lose 90% of your visibility, 90% of your mobility and you slide in a random direction? Perhaps that should be the effect if you FAIL your save.
2. Red Named Foes - make the permanent immunities dispellable or perhaps come up with a collection of packages for immunities that the red name foes get randomly. I play a Necromancer and I become a pylon whenever we encounter a red-named foe because, no matter how low or high their CR is, they ALL have permanent Death Ward.
3. Wizards - clerics get the same SP, can wear armour, get all their spells automatically (no costly inscription materials), get more hp, can swap their spells at inns, and cast their spells just as fast. In other words, they have all the flexibility of a wizard, but without any of their drawbacks. Why would anyone play a wizard? My suggestions would be to drastically cut down on the cost of inscription materials, speed up their casting time to be midway between a cleric and a sorcerer and do the same with their SP - put them midway between a cleric and sorcerer.
4. Give schools of magic that don't typically have damage an enhancement stream to add to DC, perhaps just up to +2 or so, and with a high cost. Mob's saving throws get pretty darn ridiculous sometimes and casters who focus on spells with saves (enchanters, necromancers, illusionists, etc.) can rapidly find a large portion of their spell selection useless because no matter how high they tweak their DC, it just isn't high enough for their lower-level spells to even have a chance of affecting certain mobs.