I think if anything this gives a bigger impression of James as a boss: pedantic, impatient, overbearing perfectionist, and a bit of a child, really. He gave Dave a hard time, he gave the kids a hard time ("it's a tank you idiot!"), but in the end James admitted Dave was right all along and the kids did a great job. Watching this, I never thought Dave was unreliable or unresponsive, I think he was just worried James would make more demands that would cause the project to fail. The whole project had James' childish vision and enthusiasm, but also the childish organization. Don't get me wrong, I like James and thought the show was great, but I wouldn't worry about Dave or any of the other people associated with the projects. It's mostly about James being an overgrown, fussy child.
Thing is, I didn't get that impression from James on the lego build. He was my boss for over a month, remember, and to be honest, we had precious little direction from anyone - a lot of the time I had to go demand work for people to do. My first encounter with James was my longest, and he was sorting bricks from buckets (something my family took over later on) and building bits himself. He seemed quite happy to continue doing that, but he was over-ruled by Plum, who wanted him up on site to film. This earned them an 'awwww, Daaaad! I just want to finish this bit!' so perhaps you're right about him being a bit of a big kid. Despite his protests that he has OCD, he was a LOT less pedantic than I was (remember the kid I upset, and his youtube video?) about things being done exactly to spec. Sorry, roof people, but I was proved right on the ONLY way to build the long ones...
OK I wasn't working on the house site for most of the time, so others will have a different perspective, but the only time I saw him demand a change to the house itself was towards the end - and it wasn't a change, as such, it was just that he wanted the ceiling to be done the way that had been originally planned, and the decision to not do it that way had been taken without him, and not by Plum.
Other people wanted plenty of changes - the windows went through several revisions for example - and things came down from site changed slightly so we could copy them, but other than that the only things
James wasn't happy with as far as I'm aware were some of the more friday-afternoonish independent furniture/decor creations - and really, John and family were quite a hard act to follow there!
Perhaps James came across differently to Plum themselves, who obviously had a lot more dealing with him than I did, and that's why they chose to portray him that way, but it's not how he came across to me. But then, I was getting fed up with a number of people who were being paid to be there and who weren't putting in as much effort or care as the people who weren't, so if James was being rather grumpy with Plum, I can't help but think they deserved it. There were a number of people who, had they been working for me, would have been taken aside for a 'little chat'. When you're putting something on TV, you're putting your reputation on the line, so of course you're going to expect the people who're working for and with you to make their best effort. I expect that on everything I do, whether anyone's going to see it or not.