I find Executioner just fine :| The 2 AP gain is alright. I got this Talent on both of my mages, Fane and Lohse, and it worked really well. I mean, considering the fact that mages deal crazy AOE damage, the 2 AP gain is really nice. For example, you spend 3/4 APs to use Laser Ray, right? Which deals a lot of damage. If you take down someone, you get 2 APs back, so with 3 APs, you can follow up with Epidemic of Fire, which also takes 3 APs, and also deals a lot of damage. That's not nothing. In the case of Air/Water schools, aside from the damage, you also cause stun/frozen with chained Air/Water spells as well. Closed Circuit costs 2 APs, and that spell alone makes a huge difference. Repeated procs of this Talent per turn would be too op, actually. I'd say you gain more with this Talent when it's on casters, rather than fighters.
And it used to proc multiple times... and it was SO FUN.
But yeah, you're right.