I can give some clarification on the mentioned AoO issue. The AoO issue is known, and the explanation for this issue is rather simple actually: Ai does not take AoO into account at all. This is intentional (we don't want the talent to go to waste), but clearly it's giving some issues at the moment. We have plans to fix the behaviour in the future, which should get rid of the annoyances that have been mentioned (like getting killed by AoO) while ensuring the viability of the talent.
If you don't want the Opportunist Talent to go to waste, why does Sneak cost 4 AP, this making the Guerrilla Talent go to waste.
But on the subject of AI fixes, is Larian aware that AI 2.0 is so smart that the entire concept of a Tank has been turned on its head? It ignores targets with high physical armor and the Provoke/Taunt Skill is blocked by Physical armor. The only viable way to build a tank now is to take Glass Cannon, Walk it Off and pump CON. The Glass Cannon becomes the target dummy.