Random thoughts that have been percolating since the Writers' League of Texas panel and since talking at dinner at the Montgomery County Teen Book Festival with Kimberly Willis Holt:
In the cases of both my novels I've found that the final, published plot is completely different from the one that I had at the end of the first draft. (By "first draft," I don't mean just the first output that could reasonably be called a "first draft," but also the thing that is sufficiently polished that it can go out to an editor and be reasonably assured of getting at least a personal response).
That is, notwithstanding critiques of the mss, at some point, the thing had to go deeper and be completely re-thought and re-plotted. This is not necessarily something that a critique alone is going to reveal (Your critique partners, no matter how skilled, are unlikely to tell you to just scrap the thing and start over).
So, keep an open mind and don't fall in love with your prose...