Not only that, there's one of his (many) quotes that fits nicely with this way of thinking:

"I save about twenty drafts — that's ten meg of disc space — and the last one contains all the final alterations. Once it has been printed out and received by the publishers, there's a cry here of 'Tough shit, literary researchers of the future, try getting a proper job!' and the rest are wiped."

On one hand, as a long time Pratchett fan, it would be interesting to see what ideas he was working on (I'll miss many of his characters), on the other hand and looking at other examples (cough, cough, Tolkien, cough), I prefer his legacy to be what it is today.

Its not just about the release of an unfinished novel with lots of rough edges, its our understanding of how the Diskworld evolved in Pterry's mind over the years. TCOM was a simple spoof of swords-and-sorcery epics, but by Going Postal it had become a complex world that fused magic with steampunk. The rough drafts, abandoned dead-ends and private notes that presumably inhabited those disk drives would have provided insights into how this happened.

Update: just read loopbit's response to the same post. Good point.