It may see a bit soon to talk about expansions seriously, so this is a fun, non-serious topic, at least for now! But having played the game a couple of times and thoroughly enjoyed it, I can't help but imagine some possible items for an expansion, though I would be careful about needlessly complicating this game or making it longer than it can be. It's a gem as it is. That said, though, here's what I would like to see:
1. Another race or two, allowing up to 6 to play. This would make for a very long game and a very big board, but a couple extra races would give variation to the 2-4 player games. (I confess that I miss dwarves in my fantasy epic....)
2. Special "Wonders" that each race could build that would convey a specific benefit and give the sense of a living culture. These might function like developments, perhaps granting more influence because of the awe and wonder they inspire throughout the land.. Anything that adds theme and flavor to the fantasy world and its races and cultures without making the game more complex would be nice.
3. Enabling heroes to affect battles more directly. As it is, the heroes are a strategy unto themselves, and I'm happy to leave them as they are.But I notice that variants are already being proposed and played using the heroes in the battles (and the results posted on BGG), and they sound doable and exciting without adding a lot of extra complexity to the game. It would be nice for there to be an official version of the affect of heroes upon battles. (It could be very simple, such as the presence of a hero allows one unit to ignore a rout result or once per battle enables one unit to use its special ability as if it had drawn an orb.)
That's it for me.