I wonder if we're missing the much simpler thought of "Heelys for robots?" Put wheels in the feet so it can move with a quickness, but also let them step around when they need to maneuver into our spaces.

They do have those, but the leg mechanisms don't have the same dynamic range as a humans' so they end up getting stuck in doorways, narrow stairwells, or other places which assume bi-pedals. Making them narrow enough to fit, makes them too short to reach the same heights assumed for adult humans, so they can't do the same thing.

The height vs width form factor kills the whole idea as a general solution.

might struggle to get into narrow spaces that a human could fit. wheels and legs do seem like a good idea though and a robot on rollar skates does sound awesome.