Rides such as Hex, The Haunting, Sub-Terra NEED those pre-show rooms/scenes though or they fundamentally won't work. They're narrative builders to create an immersive experience (which is what those rides are, and nothing more), so if you don't put them in, you leave guests even more confused about what the **** has just happened.
As an example, let's take Sub-Terra for example. I'm ignoring the fact that the 'actors' are there (lets face it, they're **** idiots and their characterisations are beyond abysmal), so the queue line TV's don't show much and you can barely hear them, if at all - so the emphasis of the narrative feed comes from the first reshow with the Television and guards (to some extent). That footage, quickly, tells you about the Nemesis monster, that it has eggs and that the Phalanx Control is solving the problem, so it gives you the main points of the narrative (Where you are, What's going on, What you're going to do next - location, problem, outcome). If that scene wasn't there and you then entered a small boxed room that it's floor vibrates and lights move in a completely unrealistic movement (the elevator) then you boarded a mechanism that dropped, you'd have absolutely no idea what the large easter eggs and back stabbing was and why it existed.
Now, I know that you're not all stupid and know why those types of scenes are there, to tell the story in a multimedia format that's engaging to guests - but, the design teams behind the attraction have tried to maximise the throughput of these scenes as best as they possibly can and that's in the little details of the ride.
1) The batching system with the dots on the floor and staggered queueing that they do.
2) Double elevators, so they can alleviate the problem of bottlenecks (the collection of a high concentration of guests through a narrowing, such as a doorway etc.)
3) They inform you of your seating arrangement prior to you boarding the vehicle.
4) When you exit the elevator, they have two doorways, subconsciously diverting the guests ("I was in the left elevator, therefore, I might be on the lefthand door), this is a simple trick, but works with the majority of the guests.
5) They've made the loading happen from one corner of the room and the exit to be on the complete opposite side of the room, imagine a square, corner to corner. This shape allows maximum throughput and efficiency through the room, using the central theming element (the egg) to split up guests.
6) When the show scene ends, they use increased theatrical elements such as additional strobe lighting, red flashing beacons, alarms and smoke to create a 'hysteria' and 'panic' mode, making guests move quicker to 'escape' the room.
7) Again, double elevators to exit.
8) The 'attack' scene in the elevator - this is a very clever tactic, it may just seem that this is added for the narrative ending reason alone, but in reality - it's not. Whilst it is the 'finale' of the ride, it is in fact a way of keeping momentum going in the guests. The lighting flickers and blows out, loud noises of the elevator being 'attacked' are heard, it shakes violently and the walls move in/out - all of these create panic in the guests and when you're panicked, you move quicker (aka your fight or flight reflexes - unless you fall into the 'freeze' category in which by this point, you'd actually just be stood in a corner).
9) Due to the finale 'not working' and guests leaving unfulfilled with the experience, they added the 'scare attraction' ending with scare actors hurrying the guests out by using scare tactics and air cannons etc. This scene should be the bottleneck of the whole attraction, but in fact, it works really well and due to the sense of panic to escape, the guests leave hastily.
Using the final point as an example of why a pre-show (post-show in this case) is actually beneficial to an attraction - when the ride first opened, it received absolutely dire feedback, really low sense of enjoyment from the majority of the guests. So, what did MMM (Merlin Making Magic) do? They added the scare attraction element to the ending to extend the time of the attraction, have a real 'payoff' and to sustain the feeling of panic and terror until the very last second that the guests left the experience.
In my opinion, pre-shows and post-shows work.
