I've seen a lot of these What if topics on the forums recently, and thought I'd do one myself. The question is pretty self-explanatory, but I'll explain it more. Basically, if you went back in time to early 1993 and went to ID, what would you tell John Carmack to program differently, or add to DOOM to make it better (even though it is already perfect)? Or, if you could ask one of the map creators to do something different in their maps, what would it be? There is no limit to how much you would c