My two cents here.
It isn't bashing to fairly critique someone's work and note where things aren't as they should be. Also the fact GR signed off on this stuff has to be taken with a measure of cynicism. At least I take it that way because my impression of GR is that he mightn't have really cared how accurate FJ's work was as long as he thought he could make a buck of it. And at this point of time both the Booklet of General Plans
and the Starfleet Technical Manual
were products that went far beyond what anything even remotely of the kind had ever done before. As such many of us were damned glad to have them even as we soon starting to see some things were off.
It isn't an indictment to note FJ wasn't a fan because that's not really relevant. What is relevant is his execution and in all fairness the final product is all we really have to assess. Somewhere along the line there was a disconnect. I have to say that there are too many discrepancies between the onscreen filming miniature and the ship FJ actually drew. And I don't want to hear again he was drawing the Constitution
because it comes down to it being pitched as blueprints to the Enterprise
we saw onscreen. On that point it's a significant miss.
Granted I don't know all the facts but I do have to wonder if he had the opportunity to actually study the 11 footer. Did he have access to the original construction drawings? I don't think he studied film clips of the shuttlecraft all that well because that's a huge dropping-the-ball in my eyes.
My essential point is FJ got things essentially right and he displayed a lot of good and interesting conceptual thinking, but he flubbed details that shouldn't have happened if he'd carefully scrutinized those film clips. The notion his daughter and friends were fans and were also essentially unpaid research consultants might not have worked in FJ's favour. They could study all the film clips they want but if they haven't got a good eye for detail and how to communicate what they're seeing properly and accurately then there will be a definite limit to the value of their effort.
We'll never know what we might have gotten if somebody had approached Matt Jefferies with the idea of doing what FJ did (and, of course, getting paid to do it). But fact is that didn't happen and FJ's work basically launched a market likely few suspected was there. For that I'm thankful.
For many of us interested in this materiel we basically take the approach of accepting what we saw onscreen and then trying to flesh it out without deviating too much or too obviously so as to make it all work. FJ's approach seems to have been to give us the essence of what we saw but deviating in other aspects.
Also if so many of us we're so totally enamoured with FJ then we wouldn't have dared even consider the thought we could build and improve on what he did.
His work is what it is. I think now we can just go from there rather than fretting over how he got the end result he gave us.