I think the thing that many people forget when it comes to DLC speculation is that they tend to have a theme -- something that is a large feature and sexy enough to be a selling point. It's not impossible they might forgo that ("Way of Life" certainly had a pretty weak theme, so who knows?), but that does seem to be the trend...and it's an understandable one. Paradox would, after all, be putting out something that's attempting to reach a larger audience than the inhabitants of this forum. I know we tend to run on the belief that we, the few, the hardcore, are the only fans that do or should matter when it comes to CK2, but that's just not true.
I'm not big on the idea of expanding the map further, myself, but I have to admit that "China!" makes for a much sexier DLC theme than, say, "cadet dynasties!" Cadets are something we might get as a minor feature in a DLC, especially if it otherwise fits the theme. And both of those are
way sexier than "bug-fixing DLC!"
Personally I'm holding out hope for an Empire DLC that deals with late-game realm management, or maybe something centered on Russia or the Holy Roman Empire (though the latter really missed its chance in LoR). Regardless, my impression is that, when Paradox makes veiled hints and suggests that what they're working on is "something the fans have always wanted and are really excited about", that doesn't really tend to help with guessing their intention...like, at all.