You need to remember there are constraints on what DLC can do to a games base code. It is for this reason that Super Street Fighter 4 is being released as a game and not as a dlc patch for the original Street Fighter 4 game. The base code of the game can be manipulated to an extent but the DLC cannot completely overwrite the base code. Therefore in older games, should the base code not offer the option of expanding to include features like map editors then well sorry that is just how it goes.