I think next year they might do a compete edition of the game. It won't surprise me if MKX wins best fighting game of 2015 and NRS might end up doing a "Mortal Kombat X: Fighting Game of the Year Edition". I know friends who want to wait for a compete edition of the game to save money then spending a extra $30+ on DLC.
Another MK Trilogy that somehow combines MK9 and MKX would be pretty sweet, but now that I think about it, it would probably be better to wait until after MK11 for that.