There have been some really nasty bits of Sam-bashing on this topic, and every one that I've read that's been identifiable in origin has come from an ESG.

My ideal would be for Dean to have essential agency (and monster help would be cool) but for Sam to play a necessary role in the purgatory escape, but Dean getting himself out is among my preferred options. What I don't really want is for their to be some mystery about how and why Dean is out -- I think they've played that one enough. But I can see that for flashback narrative to mesh organically with present it may have to be structured partly as mystery with clues.