Not sure that I match the "sad" sentiment.
Hitchens lived exactly the sort of life that is appropriate for his character. He lived life big and hard. His smoking and drinking habits are legendary, and he did not persist in them out of ignorance. The well known idiom "Better to burn out than to fade away" might be in some way appropriate here.
Certainly the world is worse off for the dearth of quality polemicists and literary lights who are reminiscent of what I'd consider a better time in English writing. Still, to have had such a light and to have been able to appreciate it is an incredible opportunity afforded to, in the grand scheme, astonishingly few who can appreciate it.
Death always seems tough to deal with, but it is an inevitability that, in some sense, makes playing the game of life all the more relevant, important, and fantastic.