Well, there's still a few problems in the current game (meta-game, balance, render distances), that I'd say they'd better fix those first, before they start cooking up new ideas.
The game only just got here. It's and awesome game as it is, but far from polished and free of bugs and other "growing pains".
I'd be happy to see it turned into a finished product, before even more half-done content is being added.