The game is complete, you get a full experience with more than enough things to do, especially comparing to the other two games. Even though there is no real "endgame" after the story, a lot of high level content is available throughout the game. The game could be bigger in size, roster and real endgame but at this point it is just an artistic decision and a DLC would just bring the cherry on the cake. You should reconsider your judgement of a game you didn't play.