That has been bothering me too, why Michael himself has not made an appearance - be it in a dream or through Castiel or whatever, and I don't trust Zachariah at all ( thought it may turned out that he really is the good guy, angel, whatever, after all.

Anna/Anna

Meaning that Dean is Michael? And if he said yes, he'd be Michael, not just a condom ( oh Dean ) for that archangel?