I like most of your points. Some of these are more subtle and can easily slip off your mind when you're summing up a lot of things at once.
As Guerilla is tied to Sneaking, lowering AP cost of Sneaking automatically makes Guerilla better. So Guerilla might not need a drastic change, if the 2-AP Sneaking really happens (or something similar). I find the whole "once per encounter" concept doesn't make a whole lot of sense, aside from purely because of balance reason. If it's just once per encounter, and cannot be used in combat, then it'd better be really, really good - something along the lines of instantly killing most normal enemies. As you said, it requires *a lot* of setting up just for one attack. And, the fact is that many encounters do not allow you the option of initiating combat at all.
I also wish that there were more talents designed specifically for spellcasters. There are Fire (Demon) and Water (Ice King), but how come Earth and Air are left out? I like the idea of having separate talents that boost the effectiveness of spells within these four classic elemental schools. Shorter cooldowns, longer durations, damage boosts, etc. Maybe extra resistances against hostile spells from the corresponding school as well.
There's Savage Sortilege, but then it is tied to crit chance. Late game in my playthrough, I found myself bumping up crit chance of everyone, fighters and mages alike. While there's nothing wrong with that, per se, but it somewhat diminishes the uniqueness of being a "spellcaster".
One important question when considering a talent is, How useful is it *in the long run*? Take Arrow Recovery for example. A 33% chance might be fine in a casual situation, but in the tough fights, the most important ones, a "chance" thing like that means it's not reliable (it encourages save/reload when you *have* to succeed). Not only that, from mid game on, when you have all the gold in the world and can buy as many arrows as you like, or make pretty much whatever you want, plus the fact that magical arrows are quite abundant throughout the game, this talent becomes useless really fast.
I prefer something that is reliable, and still useful by endgame. My idea is to rework Arrow Recovery into something like increasing effectiveness of magical arrows - increased duration and/or additional damage.
