A loss of a keen mind. His body could not hold him back.
Indeed! He'll be sorely missed, as both a scientist and a "rock star" science popularizer.
A collaborator of his quoted in NPR's obituary suggested that his physical and communications limitations may have shaped his mental abilities:
Toward the end of his life, Hawking's disease left him virtually paralyzed. It took an enormous effort for Hawking to communicate, using the tiny movements he could make to control a computer interface. It's tempting to say that Hawking achieved his fame in spite of his physical challenges.
But in a way, Hawking's physical challenges may have contributed to his mental prowess, says Kip Thorne, a physicist at the California Institute of Technology who frequently collaborated with Hawking.
"It was because of this handicap that he developed new ways of thinking," Thorne says, "new ways of wrapping his brain around things that enabled him to out-think anybody else in the field."
And he out-thought people with great regularity.
(Of course, the vast majority of people with (or without) similar physical challenges don't turn out to be geniuses!)