My head feels funny from staying up to 3AM, and I wrote something like 6000 words yesterday, but draft 4 is officially done. I wouldn't say complete; I've already got a scribbled-down list of things I want to tidy up, plot holes that need repairing, and the (all-new) ending needs work; this time my loveable rogue MC went too far the other way and went all straight-up cuddly on me, and I want to dial the feels back a little. But while draft 4 may still need some tuning up, I think I finally got this story running.
Granted, I thought that about the third draft, and when I went back to it all I could think was, "the story and characters are great but this prose is terrible." Draft 4 I concentrated on the mechanics and am going to have to go back in places and re-insert (and improve) some of that terrible prose to get the plot and characters back up to where they were in the last draft; I agree with what what rwm4768 was describing upthread, that some of the stuff I cut out for being inessential to the plot made for a better story and more three-dimensional characters and needs to be put back in. But overall, I think this time, I finally got the story I was trying for.
Plus, while it's cooling, I can give that insistent Shiny New Idea some guilt-free attention.