THIS POST HAS SOME SPOILERS ABOUT DERREN BROWN'S GHOST TRAIN
Clearly DBGT isn’t well suited to a pandemic, and the number of staff it needs was always going to be a problem, particularly given Merlin’s track record. I do also agree that the storyline is too confusing, the height restriction’s too high, and the queue’s uninspiring… so sure, there are quite a few faults.
I was thinking though, is part of the problem that most enthusiasts have read or seen something on the Internet that tells them how it works? If you didn’t know what a Pepper’s Ghost effect was, and you hadn’t seen anything about the ride system, would you be more impressed? DBGT was always about illusion, and most illusions aren’t as good when you know how they’re done. Maybe some of the spoilers have spoilt it for some people. The trick with the train carriage is still a very good one when you don’t know how it’s done.
From the point of view of how it works as an illusion, there are some nice pieces of mis-direction. For example, we're told to take care when we're boarding the train, because 'it might sway from side to side'. If you didn't know what the illusion was, it would be a bit of a head scratcher. If you walk up to it going, 'Yeah, it's done with mirror', then it's lost its main point.
If you've spent a lot of time wondering how a trick's done, it can be nice to find out if you're right. Like getting the answer to a riddle. But if you haven't gone through the 'wondering' stage first, then getting told how it's done too soon ends up feeling anti-climatic.