I'm glad you raised this, and it's worth following up with Brian. I think he would appreciate a lot that you took the time to do it.
Where? I think the question is how private you want the discussion to be. On one hand, I think it would be good for other authors to see this kind of dialogue, because it happens all the time. It would be good to have it here. It also gives me a chance to weigh in, and notice whether there's something in the "moderators guidelines" for CB comments that should be tweaked.
On the other hand, it's a matter of style and privacy. If it's something you prefer to keep private -- e.g. something that is a bit sensitive, personal, or has potential for misunderstanding -- then a private side discussion on email or FB might be better.
Your call -- just keep me "in the loop" if possible.
Personally, I'm not very naturally "tactful" -- If I don't make a conscious effort, I can blurt out something that stings.

So I have to work at it, adn often clean up afterwards.
BTW, I think you've done a good job of clarifying that just because
you wouldn't use a bite, doesn't mean you don't think anybody would. My only suggestion would be to ease the "sting" of criticism with a bit more "balm" of praise, encouragement, but only when you can do so honestly.
Even more, I love that a) you're doing a lot of rating, commenting, and b) you are taking the rating system literally -- as intended. i.e. The question is not "is this a 'good' bite?" but "how likely are you to use it?" That is exactly what we hoped, because otherwise a) there is no objective standard, and b) there's a huge bias toward rating positive ("All the children are above average."), which renders the ratings meaningless because then 90% are 4s and 5s. 3 stars is "good - I'd probably use it", so that's actually a pretty positive rating.
Our problem is that we need a lot more people doing ratings -- I'm stumped for now on how to encourage/incentivize this.
Finally, you're probably right that I should simpify the forum. When we started it, it seemed to make sense to have categories. But until its used more heavily, simple may be better.
For now, just post
all comments, feedback, discussion on specific bites in the "Authors Forum -- Bites" ; i.e. let's get it goig again, see how its working, and then re-evaluate the categories