This has crossed my mind multiple times as well.
However, in ‘In the Name of the Brother’, when Hook is with Emma on the ground and taunts Rumple, Rumple walks over to Hook and kicks him. But he seemed to kick him fine. and he kicked him with the leg that he limps on. Maybe I’m reading into this too far, but it keeps coming back to me.
Maybe its a price he had to pay for bringing magic to SB.