I'm actually cautiously optomistic about this change for a couple of reasons.
1. EA, if it continues to make a game, would have to make the gameplay better than it's ever been if a "generic" set of teams/rosters is going to survive.
2. Fully customizable teams, with more options for logos, unis, stadiums, etc. would be awesome, especially if this customization was available online (ala Team Builder now, for hardcore guys) and on the disk (like previous installments of NCAA and Madden, easy for the casual gamer).
3. If full customization was available online, there would need to be a way to import 120+ teams, and all of the information that comes with them (rosters, stadium, uniforms), rather than just the 5-10 teams that TeamBuilder allows on the disk currently. If this were expanded, player rosters, coach lists, and updated/special uniforms would all be available for download and completed before the game even launches, as it would be via internet. You wouldn't need to wait for a hard copy of the disk like the roster gurus do currently.