I'd contribute to the concept adding through a scripting language, but *gasp* there isn't one.
I guess other than that... there would be better artists, though I could help with that. I can't be arsed to game balance, so I'll leave that one...
I guess it depends on how the scenario making is done. I was thinking of doing something similar for CtP2, but everything fits together too tightly to make it easy to split.
Put me down under concepts and ideas generation centre.