Well, I'm with you, that it would be great to have accessory support (which 3.1 brings), but the moment you require an accessory for gameplay, mobility typically suffers and your market is cut down drastically. Of course, the controller/keyboard/mouse could be an option, and a welcome one for serious gamers.

The recommended scheme is not a replacement for a keyboard/mouse or a physical controller, just (IMO) a better way of controlling compared to trying to mimic a console controller on the device face. Again, it doesn't have to be the default controlling scheme, or even the only one: it could very easily be made an option for power gamers on the road to better play and compete with one another.

I most certainly would appreciate such a scheme.