I'm sure I'm not the only one who greatly admired him. The theme of his stories was progress; they were set in a fantasy world, it's true, but one that was frequently a direct analogy to our own past, and where the golden age was always right now. The recent books made this ever more obvious.
We have lost a great man today, but it's the way he died that makes me uncomfortable. Terry Pratchett had early-onset Alzheimer's, and while I doubt it would have mattered, he couldn't have chosen cryonics even if he wanted to. He campaigned for voluntary euthanasia in cases like his. I will refrain from speculating on whether his unexpected death was wholly natural; whether it was or wasn't, I can't see this having a better outcome. In short...
There is, for each of us, a one-ninth chance of developing Alzheimer's if we live long enough. Many of us may have relatives that are already showing signs, and in the current regime these relatives cannot be cryonically stored even if they wish to try; by the time they die, there will be little purpose in doing so. For cryonics to help for neurodegenerative disorders, it needs to be applied before they become fatal.
Is there anything we can do to change that? Are there countries in which that generalisation is false?
It's a suspiciously pleasant way to go, but I see no reason to look more closely at this. Let's just be happy he got the end he wanted.
Pratchett himself stated an intention to commit suicide before his disease progressed past a certain point. "To jump before I am pushed", I believe was the phrase he used at one point.
http://www.theguardian.com/society/2010/feb/02/terry-pratchett-assisted-suicide-tribunal
The BBC claims that he didn't take his own life, and given his advocacy I think that his family would have been honest about his suicide if it were one, but it's a reason to look more closely at least.