Spontaneously grabbing a feat is nice, but the need to meet the requirements cuts off a lot of feats and if the feat isn't situational, you are just using it as a limited use bonus feat.
Flanking Foil is the one thing that comes to mind as good for it. What else is good for it?
Improved X would have been my first idea, but with them being split into two for zero reason, being a medium BAB class and CMD being impossible to overcome for a full BAB, it doesn't seem like a good idea.