A Lobby system would also add longetivity to the game, cause people could have custom lobbies with high ap gain or low qp gain, 1 v1 and 3v1 matches, practice stages, they can have certain items turned on and off. Think of all the fun possibilities.
i'd only want a lobby system if it were like tekken 5 dark resurection...you know, let me rank up while in a obby system. Think all the fighting games i've played in recent years have lobby systems in non rannk matches...just annos the hell out of me for some reason. Dont know about DOA5 or tekken tag 2 as i havent played those. trying hard to remember if it was rank or non rank i plaed in MK but i remember a lobby system