Doesn't the deal kick in after 10+ years? I think the people in favor of this deal are hoping that by then we'll be ready for whatever they've got or that the Mullahs will all be dead by then.
Who knows, but letting Iran police their own nuclear sites, even in part, is insane; not to mention giving them all that time to hold off inspections until they've had time to hide all their illegal activity, to me is insane.
If I were the leader of the free world, I'd put cardboard cut outs of me everywhere that say, "we've got our eyes on you", and it would only cost the tax payers 100 dollars.