I don't think that anywhere can have too many activities. We each have so many different interests, and there are festivals to suit all of us. We don't have to go to them all...or any at all, if we don't want to. We're lucky to have such a wide choice as there's certain to be something that will inspire us.
Well, I would say yes there are too many, but I would also add that I don't take that as a negative aspect. The variety of events makes it easier to decide which one to attend as there is always one which is closest to your heart. I love Melbourne and all the festivals and events it offers to its residents. Way to go Melbourne.