The colors get confusing on the map and some other times even on the battlefield they could get confusing. For example blue with cyan. This can get a bit confusing because when you fight in a big battle and have both troops in one huge battalion they could get a bit difficult to identify, so we need a bigger variety of colors to choose from.
Seeing the friendly cursor on the map could really make a difference in the battlefield because you could make plans and tactics a lot more simpler. This would be very useful for every type of player and how you wanted play the game because it would give more tactical and strategic choices if you do see your allies cursor.