true enough, hadn't thought of that angle. they really pulled what I thought was (at times) a lackluster season six. they could've done SO much more with it, but honestly, they did it in the way I guess sam and dean would've done it... the brother as michael pissed me off at first, but it really worked in this episode... and michael/lucifer in the pit? a LOT of potential for future shenanigans written into the script.
I really liked the writing of the finale... it just worked, which is all you can really ask of a script.