This 'may' sound like a toggle-like thing, but why don't apply everything for the new default skin (like just leaving it, as it is right now), so all the new players are seeing that osu! is a fresh and modern game and for the people who don't like all this, adding these new things as options they can choose in the skin.ini for example (or the new skinning menu)...like en/disabling the falling X's (but peppy already declined this before) and every other option that may distract people from playing or even change the feel of playing.
I personally only miss the bumping hitcircles, after hitting them, everything else is fine for me, thought.