The piano in November Rain is more a percussion instrument. It's mostly hitting the quarter notes, which makes it easier to sing over top.
Perhaps has a more elaborate piano rhythm to it. Not saying Axl can't play and sing at the same time, but it's not as simple as playing and singing November.
That said, it's not as though the piano in Perhaps changes all that much. It's fairly repetitive save for the fills in the chorus. I'd rather see Axl engaging with the fans during the song than plunked on a piano bench to play mostly the same riff throughout the song.