Good points about balancing the teams, but I'm of the opinion that it shouldn't take an admin to balance it. Some common sense will tell you that if one team is just getting out shot, then some player changes can make a difference. Maybe some other times it won't & it's just an execution thing, but I've been on both sides.

The stack situation that bothers me the most is when a really lopsided map will get all/a lot of the skilled players on the easy side, ie: CTs stacked on Aztec vs a few regulars and some CSS noobs.