I guess I'd see hills and obstacles as the biggest problem because car engines don't tire in the same way I do. With a car, if the automatic controller gets a shift "wrong" because it doesn't know I'll be changing grade in 30 metres, it just shifts again on the hill and the engine doesn't care that it has to put out high rpm's for a bit. The car engine will be as fresh at the top of a climb as at the bottom. The car's automatic doesn't even care how long it puts out higher rpms. It doesn't even need to know if it is a long hill that gets even steeper further on, or, on the flip side, that I am about to jump out of the saddle just before the top of the hill. So, I'll be needing Predictive Terrain Detection (tm).

And maybe some yaw and roll sensors for turns.

I was thinking it will be helpful around town (or when tired at the end of a ride). It would, of course, need to know when a stop is imminent and shift soon enough that it can get to the right gear for starting. Either that or the nature of the drivetrain (i.e. inability to shift standing still) might have to change.