Well it's typical that a LOT of users leave the MK scene after a new game comes out, especially after a month or two. But with this game I think will be an explosion of excitement that lasts for a long time so will be less of an issue.
Hm, that just seems really weird to me. When a new game comes out I usually wanna talk about it and learn new stuff (as was the case with SSF4 and MVC3). Though I guess the last few MKs weren't exactly greatest games.