WWE '12 came out last year and we have already added several names to the WWE roster which are not in the game.
Sure, people can create their own versions, but they are never quite the same as the ones THQ makes, and it really would not be all that hard to keep up.
WWE always has too many superstars to put in the game, but there is no limit to how many DLC items you can release.
Here is a great way this could be structured where everyone would gain something and lose nothing.
First, WWE starts out with whatever standard roster the game would include, say 50 superstars, 10 Divas and 10 legends, and then they could create special DLC packages with the rest of the current roster.
Make packages containing two superstars for a dollar. Some fans would be willing to pay a dollar to play as Curt Hawkins and Tyler Reks, and there are a lot of people who you know will not be included in the game unless by DLC.
When new superstars are brought into the company, WWE should have THQ release a DLC for that superstar which is either free or costs a dollar.
By doing this, WWE would be creating one of the most accurate sports games on the market.
I know I would like to be able to play as Damien Sandow, and I do not want to have to use a created wrestler to do it.