To be honest at no point during this gen have I wanted more than the 9 buttons available on the 360 controller. The more buttons there are, the more complicated games will become, and for me that's not what console gaming is about. If I want complicated with lots of buttons, I'll go play on my PC.
Edit: Actually, make that 11 buttons. The 4 face buttons, the 4 shoulder buttons, the back button, and the 2 thumbstick clicks. I'm ignoring the start button and guide button as they don't actually do anything gameplay wise.