The OP beat me to this topic.
Not really sure how I feel about this sort of thing. On the one hand, I guess if I can accept movie/TV reboots and the like then I shouldn't have a problem with the literary equivilent.
On the other hand, this just seems wrong to me. No offense to Mr. Scalzi, and I do intend to give his book a fair chance, but why do this? Couldn't the publisher simply re-issue Piper's original work (and Piper's work should be re-released!)? If this was a sequel or prequel novel, I wouldn't have too much concern, but this...well, this just don't sit right for me. What's next Stranger in a Strange Land reinterpreted by Peter David? Dune rebooted by Terry Brooks?
I guess, to sum up, I don't think (on general principle) classics of the genre should be superceeded by re-writes forty or fifty years after the fact.