I wish Watterson would bring him back, but I'm sure he's permanently done with it. I'm glad that it never got over-commercialized and turned into a cartoon or an animated movie or even a live-action movie. Some things are better off just the way they are, and Calvin and Hobbes is definitely one of those things.
In a way, I think that in some small part I am who I am because I read those comics since I was old enough to read. When kids were coming to school in first grade with Richard Scarry picture books or some shit like that, I was coming to school with Something Under the Bed is Drooling and a pocket dictionary to learn what words like "nefarious" and "transmogrifier" and "stupendous" meant.
I think all of those books should be mandatory reading for grammar school kids of all ages. There's a message about human nature and the world we live in contained within most of the storylines, and the ones that don't are so funny it doesn't matter, including anything with Rosalynn the babysitter in it. The only other thing I can really think of for kids that has such great entertainment value AND actually strives to say something that kids can learn and pick up on is Fraggle Rock.