CapnZapp
Legend
One for each of the six books of an AP. That's seven in total, over twenty levels.Capn's Ideas. By having only 1-2 per adventure path you are really limiting their use. I couldn't see many people spending them for a single action in combat.
And that's just my suggestion.
I understand your issue in theory.The out of combat use could be more dramatic and powerful in a good way. I would limit it though that the GM could override in VERY rare cases when its used. Only for case of say the BBEG's overall plans where the players might derail too much. But only if you are running that sort of campaign. If its more sandboxy than probably not a problem.
I'm not sure official Adventure Paths can be derailed by individual checks - where a player succeeds where he or she wasn't "supposed to"...