I think that for Civ 5, the random number generator for attack sequences needs to be replaced. I think units should behave like they do in real time strategy games, and should attack as an army. In Civ 4, units travel in groups, but it never affects combat. If units stopped operating so randomly, it would remove unfair attack sequences like medieval infantry dying to spearmen or warriors. Ever seen the spearman versus tank video on youtube? I also think, like I said, units should attack as an army, versus the current stack method, where units challenge each other individually. Just imagine a full scale battle with massive artilley and tanks bombarding relentless infantry and planes all at once.