This could be introduced in the alliance game invite or there can be extra option for joining or creating matches and invite with level cap. The creator could decide to start game when 4, 6 or 8 players joined.
As cool as this might be, it is not likely going to happen. EA has stopped any further development of new content for this game. At best, we'll get bugfixes and balance patches.
You'll be lucky to get a bug fixes at this point.
Is this communicated on an official place? I was on the impression that new content could arrive if they could earn money on it.
