it absolutely sucks, since it's usually something sucky you decide to do and you have bargained away the usual weaseling out tactics

That's a really good point. Robin likes to talk about this. Someone may enjoy eating fatty foods more than they would enjoy being fit and healthy. But people who express a desire to be fit and healthy get more social prestige, so the optimum case for them is to think they would be better off dieting, while continuing to eat as much as always. These people think they have akrasia, but don't. If someone gives them a way to "cure" their "akrasia", they'll just end out unhappy.

I got the impression that Robin thinks this explains most or all akrasia; I wouldn't go that far, but I think it explains some.