Columbus (yeah don't know why I thought that) Has made some of the best kids movies, just to name Home Alone and Harry Potter and the Sorcerer's Stone. He's doing something right.
If by "doing something right" you mean "making soul-less, if mostly harmless, drek"....
The first Harry Potter movie was excruciating for its complete lack of visual imagination or pacing. He basically tried to cram in as much as he could that was already described verbally in the books and didn't take the slightest interpretive chance. The film was a good 20 minutes longer than it had to be for what was depicted, and is only out-done in its sheer monolithic molasses-like movement by the second film, also Columbus-directed, which did the same thing as the first film, only injecting melodramatic pauses into every conversation and plot event.
Columbus is good at slapstick comedy. Home Alone, Mrs. Doubtfire, all passable and reasonably funny, even if Home Alone relied enormously on physical Jackass-esque laughs. None of them are particularly atmospheric or visually interesting, or even especially well-paced, which is going to be pretty darn critical in the Hobbit.
(credit where credit is due, the guy
did write Gremlins and the screenplay for the Goonies)
As PJ demonstrated with LOTR and Del Toro at least conceivably with Hellboy, the Hobbit is going to need a director who isn't afraid to take risks with the material and inject a bit of themselves into the creative process to make the translation from page-to-screen work. I just don't think Columbus is that kind of director.