I think there will be a MK10, it won't be like a super crazy sequel, but a revision of 9 with a new story mode and more characters, they will just call it 10 to avoid the stigma of "super" versions. They have already said they want a game to come out around the same time as the movie next year, and with the way WB is now randomly supporting MLG and the fighting game community they probably know that MK9 as is will not last a whole lot longer in its current form, patches alone can not fix it.
As a DC fan I hope to god they never EVER try there hand at a DC fighting game again. MKvsDC was straight insulting, not because of it being a bad game, but because it was a MK game with DC skins, it does not do any of the characters justice at all. Like marvel, a DC fighting needs to be crazy and flashy as shit, with air dashes and hyper fast gameplay. Need flying characters and lasers everywhere.
Though I suppose they could always announce SM2, which well I think would be the wrong move, I would fucking love it, its the best MK game, even though they didn't actually make it.