Really interesting post; thanks for sharing it!
I don't think we'll ever know the full story behind the closure. The specifically interesting thing is that when it was closed, it was announced as returning. How much internal drive there was to keep that promise is something we'll never know, nor how realistic those claims were.
In any case, a few things I can add...
This has been floated around a lot and though I've never actually looked into it, I assume the change in legislation is true (I believe it's an EU thing). As you say, Tidal was always clean and treated water, so unaffected (fun fact: it is one of the most expensive rides to run because of the cost of treating the amount of water it uses).
Now there's always been questions about this legislation. There's been suggestions that it only affects newly built rides, not old rides. So stuff like Loggers, Rumba Rapids, The Flume, Dragon Falls, etc would be fine. If that's true, then we're fine. If however it needed to be done by a set point, then there's a major problem. You need to create a closed water system around a lake (since the treated water can't go into lake water). How do you manage that in Loggers' situation with Loggers' layout.
Not saying it would be impossible, but that would be very difficult.
I can't comment on Pirate Falls or The Flume, but I believe Dragon Falls' work wasn't related to this new legislation per se.
The rockwork around Dragon Falls needed removal because it was effectively falling apart. Equally a lot of work needed to be done with the ride's trough. Maybe that was in some way related though, I don't know.
Hmmm, this bit I have some scepticism over.
Thorpe have gone for a double hit with their more recent large investments. Saw had Saw Alive. Swarm had Swarm Backwards. I think it's only natural to expect they had budget planned to do something to Ghost Train for 2017. Do I think they always planned to re-do the VR and extend the building for a new scene? Probably not, no. But they will have had budget for something. And if they wanted to, there's a chance they could have gotten more.
Now it's certainly possible that any budget for Loggers could have been siphoned over to ROTD. My thinking is that that doesn't really match up with timings. If Thorpe were planning to open Loggers for 2017, and they had the budget to do so, there would have been some level of commitment to that by September-time, which was when ROTD was in its finalisation.
I'm also aware that by 2018, Thorpe were stating that reopening Loggers would be an investment that would cost millions (I seem to remember hearing figures anywhere between £3m-£8m). I'm sure that figure increased as time went on, but if they did have budget for that secured to reopen it in 2017, but didn't open it, they would have used that budget elsewhere. The ROTD changes certainly wouldn't have used up that whole budget, and none of their other 2017 changes would have either. So something wouldn't add up there in my opinion.
To add my extra thoughts: as I said, by 2018, there were still talks of reopening Loggers. It was something that was being explored, to the point they had figures of how much it would cost to reopen, and some theming concepts. That would suggest it was still in some way feasible. The big issue at that point is then is it worthwhile? Loggers Leap was a decent log flume, but is spending many millions reopening an old flume the best way to spend money (even with a retheme or whatever)? Arguably not.
For some context here, The Walking Dead retheme of X cost about £1m. Spending at least 3 times that to get an old attraction open, plus increasing running costs for the park, is a lot to think about. Especially when you're getting to the point that you could probably build a new log flume for a similar price point.
I think in many ways, it was always a pie-in-the-sky idea trying to get it to reopen. When it closed there was always an air of pessimism about it ever reopening imo. It was great to try, but it just never seemed likely. And yet, I don't think they've ever truly given up.
I'm sure some remember back in 2019 after it was announced to not return, there was an auction of old ride parts announced. That auction was quietly removed and never mentioned again. I heard some rumours that was in part because the park changed their minds in case they decided to explore reopening it again. I've even heard that the work done in Loggers station for Creek Freak Massacre was done in such a way that they kept the core of the ride in tact (ride console, conveyor belt, etc). Not sure quite how true that it, so take that with a huge heap of salt!
I think the story with the rapids is different. Their features were changed, tamed, etc after the Drayton Manor incident. Internally, Merlin made the decision to tame their UK rapids ride to try to prevent people standing up during the ride. This was also accompanied by other things, such as ride spotters around Thorpe and Towers' rapids in particular.
If it is linked with the change in legislation (which I doubt it was tbh), it certainly would raise different questions about Loggers' closure. The changes to rapids happened mid-way through 2017, so I'd find it hard to see why they would have not run Loggers, because of the legislation, for the prior 18 months when they could have.