More ideas:
-customizeable court for home games
-the ability to change your team's name
-a logo builer feature-no urls
-Press releases (or at least something else on the Overview page)for non-Supporters so the Team Overview page doesn't look empty
-customizeable player names and looks (along with more hair & beard styles)
-player trades and the ability to drop players into free agency, where they are placed on the transfer list w/out an owner
-players placed in free agency (mentioned earlier) instead of retiring after the team is given to another user, only retiring of old age or a career-ending injury
-reserves for the all-star team - managers could put them in the starting 10 if they think they would play better, or if one or both players at a position are hurt.
-league commisioners - users in a higher division could enter an election for a league and get voted for by the users. they would have a "League Overview" page where they could make a league logo and other stuff. they would also get to vote for the MVP.
-selection of logos for the national team - either the manager could choose or the users from the country would select a user created logo entered by the creator.