I'd say this is a rather narrow-minded way to look at it, without seeing what software devs can dream up. In some sense you could argue the iPhone/touch is *less* restrictive because the interface is whatever the developer dreams it to be, and it can keep changing/adapting on the fly. "Buttons" or hotspots only appear in context both where and when they are needed, and your fingers (plus gestures) become a part of the game. The interface could theoretically be completely non-intrusive, only appearing when necessary.
I'm expecting/hoping software developers will blow our minds with creative ways to interface with a game, instead of the traditional D-pad with 2 buttons. This is an interface like no other that a game developer has had access to, hopefully people will find ways to really take advantage of it. I like to think of it as imagination being the limitation, not a fixed number of buttons.