Lance Fortnow of the blog Computational Complexity has, I believe, the definitive word on the P!=NP paper by Deolalikar (saying in a sentence what I couldn’t quite manage in two pages):
Proving P ≠ NP will require pure genius but you shouldn’t need a Fields medalist to verify the proof.
Secondary message: a good way to determine if a proof will work is to count the “clearly”s and “should be able to”s: more than one or two and the proof likely will fall apart at the slightest breath.
I agree with your secondary message, although I would opt to preclude “should be able to” entirely. As far as Fortnow’s contention, though, I’m not sure I buy into it. He cites two major results where an undergraduate math major (allegedly) could verify the arguments. That’s great, and more power to the authors, but I’m pretty sure that description would not apply to Wiles’s (second, correct) proof of Fermat’s Last Theorem. So was Wiles wrong?