I think as others have alluded to the real problem is departmental disjointedness.
Cuz you'd think the process would be thus - we need a new attraction for x target audience, we have y space for it and z budget, from which the team(s) design a thing that meets ALL the criteria. But it seems to be all disjointed and then a scramble last minute to force it all into a necessary box. Marketing decide late in the day to change the target audience, the design team being too fanciful for the budget and having to cut back crucial elements and the legal guys only making it known after money has been wasted on planning applications that the local species of frog cannot be disturbed.
Merlin aren't alone here - my favourite example is Skyrush, because the general manager of the park literally said that the winged seats offer families choices. ****ing moron. But the sad thing is that Tussauds used to be REALLY GOOD at this gelling of experience to marketing umph. What happened?
I instinctively want to blame marketing for this crap, but their reliance on the absurd gimmicks is created by poor products. If you've got a cool new ride opening (as was the case proven with Smiler), it sells itself. It's a huge problem that is exacerbated by insisting on having opening dates that cannot be met instead of soft openings like the rest of the industry, or lying about mannequins loosing arms and worlds firsts.
Everyone has been saying maybe Icon will give Merlin a kick up the arse and prove this, but Smiler already did, and here we are back where we were in whatever year it was Thirteen opened.
Like I said, everyone just gets amnesia every year.
As for the Wardley thing... That's both hilarious and so upsetting. But it begs the question, WHO designs layouts? I always got the impression that the parks would give a space and some elements they want and the manufacturers would have one of their guys do it, explaining why they are so rarely ... er, narratively paced. (What I mean here is that they don't go from beat to beat like other forms of entertainment do, they don't present an experience the way a creative person would. A few coasters do, and my favourite and best example is Tatsu. It's high up and conveys flying well and builds up to the signature element. Most coasters, good or not, just fill a space and do some stuff without much care for this. They're engineered, not designed. Waffle waffle waffle.)
Really need to remember to just straight up ask the manufacturers next time I have the opportunity. If anyone reading this ever is at one of the trade shows, please ask around.