It's rather improbable that a whole theater will be "modded". Reasons:
a) The user-made maps will be limited in size. Not sure how much but I guess they won't be useful for anything but gangbanging at 500ft between two bases.
b) User-made aircraft will not have the "full FM" package SoW offeres - this will be limited to creations of Maddox Games or user-made aircraft they deem "perfect enough" to be considered "canon".