Sadly my dream of a controller that also makes toasted sandwiches is still a ways off
Never mind the toasties, I wanted one with the equivalent of sat-nav. It could shout out helpful advice, like: "RELOAD you tool, can't you see the on screen prompt?!?!" or " I can tell you where Geralt's supposed to be looking, if you ask me nicely. If not, well, you're $£%^&*".
Or "Left, LEFT. LEFFFTT, you were supposed to run over the policeman you fool" for GTA. And for a little fun there could be smaller dlc packs where the voice/comments change. So Cortana - if she returns- etc. could put in guest appearances or something.
And if developers wanted to go all HAL and say "I'm afraid I can't let you do that..." if you're doing too well that'd be fun too.