Head Start: You are actually out of your mind if you think +5 starting AP is anywhere near balanced.
As an example: Quickdraw. Widely considered to be one of the best talents in the game, and with good reason. What this does is that it essentially grants you 4AP (less than 5), but sets requirements for how to get it (you need to spend 12AP on normal attacks -- not special arrows, not skills, just normal attacks), then specifies how you can spend that extra 4AP -- again, not special arrows or skills, just normal attacks. And it's almost impossible to unlock the first turn of combat. Even with a mountainous prereq of Marksman 5, Quickdraw would be hideously underpowered compared to a +5 starting AP talent which you can use on anything.
Quickdraw can give you far more than 4 AP. It reduces the AP of ranged attacks by 1. This means that every time you use a ranged attack, it gives you 1 AP. If you only attack 4 times in combat, then you're correct. If you attack more than 4 times (which most rangers will), then you're wrong.
ADDITIONALLY Quickdraw reduces the 'buy in' cost of making a ranged attack, which allows for more flexibility. You are now more likely to wind up with 'just enough' AP for a ranged attack, and less likely to waste AP by having 'not quite enough' for another attack.
Both of these effects last throughout the entire battle.
I can see giving Head Start a requirement, and I can see reducing it's AP value to 4, but reducing it to 1 makes it worthless. I would not even consider it spending a Talent point on it. One single extra AP per fight is completely negligible. My glass canon characters WASTE more than that on most turns, simply because they regenerate 16 AP per turn, and usually are left with 2 or 3 that they can't cast anything with.
