I don't disagree about Dean's goals. It's more a question of his motivation. I think it's important that, although his first instinct on thinking Sam was dead was to go kamikaze, he nevertheless was persuaded from it by the need to save people. I do think he genuinely believes that, if anyone can save the world, it's Sam. I also think that we're seeing a return to his season 2 mentality where he believed that Sam deserved to live, and he didn't.

I actually have a lot more I want to say. This is a subject I could (and would love to) discuss at length! :) Gonna have to get back to you on it, though, as I have deadlines to meet at the moment (grrr boo hiss)