I just got a great code review and I wanted to reply to it because I had questions. Of course the character limit was exceeded very fast.
Code reviews are somewhat different in it's nature than the content on other Stack Exchange sites. I'm sure the average character count per user submission is much higher.
If it is not intended to discuss the code but let the reviews stand for themselves then maybe I'm wrong but I felt the urge to write huge text in reply and I couldn't.
Since the site is still beta, I wonder if you might take this into consideration.