I think it would be fun to have the ability to create a team (Name, Kit, Stadium, Logo) and be able to put whatever players you want on the team. The team would be just another "Adidas All-Star" except with your own personal flair and players. Make it to where you can play with them in offline modes only.

EA HAS done is before with one of the NHL games so it is possible. They have done it in madden as well. It's an easy way to make a team with all your favorite players without having to transfer all the players and save a new roster.

I think it would just be cool to have your own creation apart of the game.

Someone said that " if you really want it, you already can. (as you say in your post) so it's not necessary to put in, EA should focus on different things imo"

I think you are right but I'm doing it more for the customizable stadiums and kits.

Yes I can put all my players on BVD with transfers, but it would be fun to have my own team.

EA did this in madden and stadium customization was kept simple, but with plenty of different combinations that made the experience pretty neat.