I believe that it's incredibly difficult to come up with a truely original concept. A lot of games that seem original are still often derivative of other games! Wetrix was really just Tetris with water. By dance games do you mean shite like Space Channel five. If so they are just reaction and timing. I am sure that type of concept has been done before the consoles arrived. Just tarted up to seem like something new.
This topic seems to have changed focus!