Can't say I agree that we've put up too many. Three isn't a lot.
Our hands were tied once Kompany got one, I think. He fully deserved a statue, but if you give Kompany one you can't not give Silva and Agüero one, since their contribution to the club and importance to the fans is at least equal to Vincent, if not slightly higher.
So it was either make three statues or no statues. Personally I'm much happier with three than none, but I really can't see anyone touching that level for a long time now so it could well be that in thirty years we still only have three (not counting the Bell, Summerbee and Lee statues that we're expecting to pop up soon).
I think it just feels like a lot because they all left within a few years of each other.