Fix the broken skills.
Last I heard, Crossbow Mastery didn't add the damage it says it does, and True Shot just plain doesn't work.
I think that there's also an error with the Deadly Gift's Death Scorpions, they start at Level 100 and go up to 500. I think that's supposed to be level 10 up to level 50. Right now, they kill things fast, can follow you with Aura of Command, and practically never die. All the player has to do is collect the loot afterwards.
The Divine Eye doesn't remove the fog of war, so it can only explore areas you've already explored, or else you just move it blindly in a field of black. That's worthless.
(Maybe not broken, but questionable)
The Ranger's Sight skill is redundant and inferior to Elven Sight, and it requires a much higher level to put points into it despite its inferiority. Either swap the sight bonus of ELven SIght and Ranger sight, or give Ranger Sight a bonus, perhaps a bonus to bow/crossbow damage?
The Freeze spell only works on enemies below a certain spiritual resistance, but when that spell is on a weapon, it ignores that requirement and always freezes.
Resurrect is awesome because when you leave an area, enemies you resurrected turn back into regular enemies, letting you farm them for XP and items. (I don't mind this so much, it's not much different from the Heaven's Blessing skill). Is this intentional? I'm thinking it isn't.
All other weapon masteries seem inferior to the Sword and Mace Masteries, which add percentage-based, not fixed bonus damage.
Withering Curse would be good if not for the problem that most enemies you want to use it on have high spiritual resistance, and are thus immune. That may be intentional, but rather seems to defeat the point of using that spell.
Bug Report: When you rapidly open and right-click to close a container you've never moused over, sometimes extra items appear inside it. I discovered this in the vampire cave, although I didn't try doing that elsewhere. I was able to repeat it, but I haven't tried on other chests. It didn't really produce anything super, but it did produce extra free stuff. I know because that chest usually only contains just the boots and a Medium Strength Charm.