Definitely, the contents of enemy within would make for some interesting elements. How could I miss that? Thanks for the heads up!

Any other suggestions?

Given the kind of environment the Xcom world is though, character development is going to get interesting, considering the implications of so many life-changing events and discoveries going on...

That said, I believe that a combat heavy Xcom roleplay would still be wasted potential, as Xcom has always been about the story as much as it is about the gameplay- and what is interesting is that the game has always allowed us to write our own stories, and I'm sure plenty of fan fiction writers did just that.