Oddly enough, I do recall the explanation of the "modular structure" of CMx2 from the pre Shock Force days, with the one "Base Game" and ability to plug in "Modules" containing additional content, like hanging ornaments on a Christmas tree. It seemed to me at the time, that the "One Core" idea was brilliant, and I had always assumed CMx2 had those capabilities.
But you are saying, for want of an analogy, that there's no way to upgrade the tree stand without buying a whole new tree first?
If that's true, you guys got 90% of the way towards "Future Proofing" Combat Mission, without even realizing it at the time. Just goes to show how good these games are.