Verbs like "fetch slippers" or "make tea" would make for adorable animations. Maybe once per day he could actually give you tea, even :3
It'd also be awesome if they had an expanded chat AI (like Cleverbot/Smarterchild). I want to tell Mr Butlertron that I love him!
I'd also like to be able to chat with him outside of my home street. Maybe I could have him do things for me while I was out exploring? Maybe he could tell me if I have mail or something?
Also, hats! Butlertrons need hats. Top hats especially.