No big surprise really, he's had a good run and it hasn't always been easy on him. I'm just glad I finally got to see him (and William Shatner) at Dragon*Con last year before he stepped out of the public eye. Alas, I never got to see or meet DeForest Kelly, and I have yet to meet or see Nichelle Nichols, but I've spoken to the rest of the original cast, however briefly. They were my heroes when I was a kid, and I still go back to rewatch the original series from time to time.
That said, I think it's also time for the Star Trek franchise to retire.