To be honest I think if you go into Smash while having a very strict list of newcomers you would be satisfied with, you're going to have a bad time.
Either that or not being open to choices you don't know much about. Like, the last two games have been the stuff of legends for me because I was open to the additions. Sure, some picks not getting in stung, but the net gains of Ridley, K.Rool, and the return of Snake (and the other vets) is simply awesome and made up for it.
I don't think I've ever been stingy, but there are a few characters that I think are...weird or boring. But I won't say anything about that at the moment.