Honor the potential, before the bloom. [Like the sunflower here in my garden...early draft.]
On the other hand, if a piece is heavily revised, and if you want everyone to say, 'perfect!' Then it's too finished-- and you're too invested in the piece-- for critiquing to do much good. [Except, you know, to burst your delicate bubble-- not helpful, btw.]
So when is a piece just right for feedback?
Here is an excellent guest post by Jennie Nash on the 10 do's and don'ts for writers seeking feedback. This Writing Life blog by Christina Baker Kline is a real treasure for writers...especially if you're writing a novel.