Move and/or shoot could work. If you had three "moves", with options being move, shoot or go into overwatch, it would not be so different from the original. Only two moves would be something of a dumbing down.

It's funny going back to turn-based after all this time. I downloaded the free Fallout from Good Old Games mentioned in the offers thread. While the combat works fine, it is very "gamey" and a little slow. I can't say I lament the move to real time in Fallout 3, which seems in retrospect a remarkably successful updating of the franchise. By contrast, Firaxis seem unusually conservative in their ambitions. I wonder if there is anything more than a niche market for this kind of game?