NME has just said basically the same thing, but I want to chime in in agreement. I think most of the folks who think this would be a good move for the Kings do see Okafor as a game changer. Nobody is accusing him of being a superstar, but he would add defense to a front line that is relatively lacking in such, and while we are rebounding fine right now, as George Orwell once wrote: "Two rebounds good, four rebounds better!"*
New Orleans would be dumping him largely for salary purposes. As has been pointed out, this would drop them below the luxury tax this year and save them $4M, rather than the $2M difference on the contracts. He appears to be through his injury problems, he's a very consistent 14/10.5/2 player, and he's 27. There is always the spectre of caveat emptor, but here I think the caveats are reasonable.
I don't think we're going to get Okafor-type value in the FA market this year, and I don't think, at this point, that we're going to find a franchise guy in the draft. If a rookie 'Reke and two "young" vets in Martin and Okafor give us a legit chance at the playoffs this year with a cast of improving kids (JT, Spence, Donte, Omri) what might happen when the kids reach full potential, and we've had a chance to tweak here and there? I like it as a bold step that says "the talent acquisition phase of the rebuild is ending, and the improvement phase is beginning".
* - I might be misremembering the Orwell quote. Something does not quite ring true to my ears there.