I've been playing a Gunslinger for a week or two now (been loads of fun), although my style isn't as precisely mechanical as others, I do have an observation to throw out there.
I think that Grit as a pool, although it right operates with Wisdom, should probably be Charisma-based instead.
While Wisdom does represent being aware of yourself and your environment, Grit doesn't feel like a extension of your Wisdom to me. Grit is "fluctuating measure of the gunslinger’s ability to perform
amazing actions in combat, both offensive and defensive." To me, that sound more of something to do with the ability score that rarely sees play, Charisma.
I like to think of it this way: A gunslinger is forcing things with their personality, shooting and daring to do things that impress others and leave them a little slack-jawed. Also, favoring Charisma for Grit rewards the Gunslinger for the Charisma-based skills the class obviously favors: Bluff and Intimidate get more interesting when Charisma is tossed in.
I've been talking with my GM and we're going to try it out in our next few sessions. Its a subtle change, but hey, thought I should mention it.