I filed about 10 or of them. Most of them have been addressed in some direct way or been made obsolete by other changes that addressed the problem indirectly. All in all, I'd think the success quote is about 70%.
The suggestions that saw no responses have been improvements that would affect the core business idea behind Google Plus in some way. I believe they are still worthwhile implementing, but not doing it now has the advantage of not confusing the current user base (cf. the reaction of power users/noisy adopters to the Google Reader changes of today).