How likely is it for AOM to get yet another expansion?

I know that I am probably in the minority, but I really like the Tale of the Dragon, as I remember the days when I'd imagine getting to play a completely new culture (and not have to sacrifice an existing one, which was the case when I'd install a Celtic or Slavic culture mod), and was really excited when it came out of nowhere.

However, it's been over 5 years now, and I am beginning to wonder if we'll ever get more cultures to play with? I look at Age of Empires and see how many cultures do those games have, meanwhile AOM only has five.

And if that's not possible, how likely it is to create a framework that would enable modders to create new cultures without having to replace existing ones?