More of a guess than an answer here : if Drums ever get added to Rocksmith, it would probably not be in the current release of the game or any major update. the Realtone cable isn't really suited for accoustic drums, which are rarely "in tune" relative to another drum set, and E-drums have a lot of potential but using midi rather than jack out. Also, the current GUI and Psarc format would probably need a partial rewrite to make it work with drums, and the 1300+ songs currently released by Ubisoft would also need to be updated Rocksmith is a niche-game, but most guitarists can afford or already have an electric guitar, which isn't the case for drummers with e-drumset. So it is very likely that it will never be added. But we can always dream : I think the main issue with rocksmith right now is latency. An ASIO-Realtone soundcard with midi IN could "easily" be done for an entity like Ubisoft, and could open possibilities for a new Rocksmith release.
