Now we have 'suggest an edit' turned on and the Sun didn't go down. In fact, the queue is almost always empty. And although people tend to approve edits a tad too fast (~20 seconds, from my observations) and miss funny stuff sometimes, it didn't reduce the quality of the site in general.
Then, it seems even more logical to allow comments from low-rep users, after they are screened in a similar fashion.
In particular, editing other people's posts requires much more responsibility (and reputation) than posting a comment. So, I really don't see why one should be allowed and the other one not.
It would also eliminate the need to handle 'should-be-a-comment' answers, which are now heavily flagged and downvoted. Thus, community effort is simply transfered from one area to another, while making the process a bit more logical and pleasant for new users.
What do you think?