Modding the game itself is good idea but how about "We Creat our own DLC" which is contains mod texture/model of a costume or a weapon so that even without DLC can be able to view your created mod texture/model just like they mod the
Dissidia 012: Duodecim Final Fantasy
GEB 1.6 DLC Japan...
Current progress is at 29%. 11,603 strings left to translate before they apply the translation in the game and do some test runs on it. The project will prolly take a while but I must say that the project is going smoothly and quite fast considering the translation progress reaching 29% already...
here's the updated website of Yugioh Tag Force Special. http://www.konami.jp/gs/game/yugioh_tfsp/game/ and there are some new OCG Structure Deck called "The Secret of Evolution" and "Extreme Synchron" ( December 06, 2014 release ) also included in this game