It's kinda hard to regain that earlier sweetness when apparently Kripke's vision all along was to pit the brothers against each other in a cosmic battle in S5. Once the magic is gone, it's quadruply hard to get it back - as in marriages really. I agree with you (ghyste) that the writers didn't fully patch that up - in fact, I thought their efforts were trite, even though I really wanted to believe and be transported back to the feeling of those earlier seasons. Maybe S6 will get there.