Et:
Thanks for that very well thought out piece; I think you have touched on all the relevant points.

It's pretty rare to find a review that gives a kayak a bad rating. Sea kayaking is a small market (and shrinking fast), and homebuilt and custom boats are a tiny slice of that, so it does seem as though one is being critical of an acquaintance to say anything negative about a design.

People don't want to say negative things about boats they own, as they are thinking of selling 'down the road'. Most online reviews (at the old paddling.net site) reflect that - even well-known 'problem boats' get 9/10 ratings.
If we've invested a lot of money and labour into a build, it's even tougher to admit the result isn't very good.
If we, as builders, are lucky enough to know an expert paddler who will take the time to paddle one of our boats, we will still be treated too kindly. It is (fortunately?) rare to find a paddler who is so hardened that the feedback on our latest 'pride and joy' will be devastating.

The reviews in (defunct) Sea Kayaker were probably the most honest, but even there you need to 'read between the lines' to understand the drawbacks of a boat.

Privately, I have had expert paddlers share with me some 'brutally honest' opinions abouot commercial designs but that is no help to the neophyte paddler. And, as you point out, experts appreciate boats that others may find intimidating. Even more to the point, beginner paddlers tend to like 'stable and comfortable' boats which usually aren't very seaworthy or seakindly, and which limit the paddler's skill development. (It's tough to teach edging to a beginner in a boat that's a wide barge, etc. .)

Most of us in the 'builder community' haven't paddled together, and if we have, it probably wasn't in very difficult conditions. So it's tough to assign a value to our opinions.

It would be helpful if designers (and reviewers) posted a 'Paddling CV' with their 'paper qualifications' ( ACA, BCU or PaddleCanada) as well as their experience in different paddling environments.