Regarding that "Don't Forget To Add A Comment!" thing: it's cute and all, but I'm sure some members will feel pressured into leaving a comment they don't have, and others will get (possibly useless) comments they didn't ask for as a result.
Even if we're given a few pre-set choices to choose from instead of full custom, it'd be better than nothing. Or heck, make the feature toggle-able, if nothing else. That's probably the simplest solution, come to think of it.