Well, this has generated a lot of discussion! I'd like to add a few more opinions of my own based on what's been said. I don't think this was rushed, or a cash grab, or released 'unfinished'. I think that it was painstakingly made, with skill, by people who wanted to produce as faithful and accurate a version of Heathrow as they could. It's not garbage by any stretch of the imagination.
As I said in the video, I feel really guilty about being critical of an add-on that has had as much work put into it as this clearly has. I think, because this was less positive than a lot of my recent reviews, it's very easy to focus on the negatives. This is, as I said, a "pretty solid representation of the airport" and "has plenty to recommend it". It's not the Heathrow of our dreams, but that doesn't mean it's bad.
Finally, it's really commendable that @iniBuilds have taken on board so much of what has been said by me, by others in this thread, by people in the YouTube video comments and by people on their forums, and are actively working on fixes and improvements. There aren't very many developers who are that responsive and that keen to improve a product after release.