That's why you're a teacher, not a a critic. You can't simply take a lesson and put it in one liner, while you can do it with reviews. Also, teaching through the internets is impossible without losing a lot of what makes personal teaching good.
I quit doing feedback threads because people don't actually read your feedback except for a small few. There have been like 5 people out of the 40-50 that I actually enjoyed doing feedback for.
Tis really been on my mind lately. However, I got to consider things around me. First, a few peeps read my work, so how can I give advice when I myself have nothing to show?
Second, as a former literature teacher, I can give technical feedback. However, lotsa authors don't even know what exactly tbey want reviewed, counting on the reviewer to know what should be given feedback.