I think that PMMM's fate in J-SaiMoe 2013 will probably depend a lot on the quality of the competition. If PMMM ends up facing the sort of competition that Saki is running into this year, then PMMM might win it all again even if they do face a bit of a backlash for doing so well in 2011.
Looking at the world of anime right now, I'm not sure who really stands out as "girls to watch" next year. I guess maybe a Little Busters girl? Or somebody in Chunnibyou?