http://www.gamespy.com/articles/994/994234p1.html

This is GameSpy's list of the six "most pointless game controllers" ever made, which offers up a somewhat humorous analysis of just that.

What I noticed about nearly all the controllers in question is their unnecessary complexity. They tend to feel gimmicky and pointless.

The moral of the story, in essence, is that sometimes, simple is better. With simplicity, you can build from the ground up. If you have a simple baseline to work with, you can build off of that and come up with something special and original. And that's one of the best qualities any designer can have: the ability to create something new and exciting out of something simple.