I personally think modern controllers totally suck. It's mostly this way, because that's what modern "hard-core" grognards like. And when I say "modern controller", I mean anything that is some variation or improvement to the PS2 controller. This controller is actually too clunky and complex to further gaming.
For most 2D games an arcade stick is ideal, and I really think 4 buttons should be the max. For 3D games, there need to be more advances in the Wii remote & nunchaku design. That is the right track, but there is a lot of room for improvement.
Also, sometimes a touch screen or mouse is the right controller. And back in the day we had light guns and trackballs and all sorts of other controls. I would like to see more experimentation in the types of controls that are used in various games. As it is, most games are just designed for the PS2-style configuration, which I would call a one-size-fits-none design. It's not suited for any type of game in particular, but it's more about a controller that can somehow play every game, even if it controls poorly.