Another swap will keep the roster slashed, keep the content slashed, etc. We all know very well that there are people here to do not care about content and more of just gameplay. However have you read the reactions to a small roster? It's game-deciding to most people.
Put your own desires aside. Put the forum's desires aside. Think of all of the comments. All of them from any site. Facebook, youtube, etc. Majority want characters. Majority want flash.
You say fans have been saying this for years. I have only seen it on this site and every once in a while on youtube. It is a minority. Only major, major fans discuss this type of stuff on the the Internet. The common fans are the masses that show up. The common fan; the common purchaser puts down simple comments like, "I really wanted _______ to be in. Guess I won't get this game."
Expanding on RB would do nothing for the people who dislike it. You'll hear the same complaining from then. An entirely new game wont survive.
If only there was more time. If there was more time, I wouldn't be saying all of this. HOWEVER in one year, it will bury a game if they created everything from scratch.