Just because YOU would hate to do it does not mean there aren't people out there who would LOVE to be able to do it. Even for offline dynasties i'd like to be able to control more than just 12 teams. And be able to import more than just 12 teams. In MLB the Show, I control every team. I only play the Yankees games but I like to have roster control over every team so if there's a trade in real life, I can always reflect that in the game. Same thing with NBA 2k13, I control every team. I play all the Heat games but I also play a lot of other matchups when the games are interesting, like if it's the Thunder vs Lakers or Knicks vs Celtics. It also allowed me to make all the trades and get the rosters as accurate as possible.
Now in college football there aren't trades, but I'd still like to be able to control more than just 12.
Teambuilder gets NO love from the NCAA team since they added it. Teambuilder teams still only get either all white or all black cleats which makes the entire uniform look generic. Most underutilized feature the NCAA team has ever added.