With PJ as producer, it's fairly likely that they'll be able to get much, if not all of the team back from Weta, as well as Alan Lee, et. al. With this in mind, PJ's absence from the director's chair might be barely noticable, especially if Guillermo Del Toro gets it (heavily rumored.) Pan's Labyrinth and Hellboy weren't without their flaws, but I think with the support Del Toro would get from the LotR production team, it could work very well.
The Hobbit is such a different type of story from LotR, it might be nice to see it told with a lighter touch, while keeping the feel of the world intact. Which would totally happen if enough of the production team comes back. Also keep in mind when you're talking about Peter Jackson, you're not just talking about him by himself. Fran and Phileppa go everywhere he goes (particularly Fran.) It's like a 3-for1.
It's a gamble, but it's better than, say, Jerry Bruckheimer producing and Stephen Sommers directing (shudders).
So say we all, yo.
