I understand wanting to keep the surprise, and ordinarily I'd advocate for that exact approach, but there really aren't any surprises on the WDW train ride to spoil, and for me that's the problem, haha!
It sounds like we just value different things on train rides, and that's fine. If it were up to me, the Adventureland stretch would have something to look at too (and at WDW you're not even looking at trees shielding you from Jungle Cruise-you're looking at trees hiding a service road, and JC is on the other side of the service road), but it seems like all of the Disney parks have collectively decided that if there's one section of their train rides where it's fine to look at nothing, it's Adventureland, which I suppose fits the theme but just doesn't interest me. That being the case, you might enjoy the WDW RR more than I do just because it sounds like you might better enjoy the sense of removal and separation you feel from the rest of the park, which is typically more pronounced than on the DLRR. In which case, I'd also recommend their riverboat and TSI for similar reasons.
DLRR was down for about a year and a half, and they did actual enhancements and even let guests go and visit the trains/stations/etc during construction. WDW RR was down for four years and they...did nothing. Just speaks to the difference between the two resorts at the moment in a very sad way.
I'm having a hard time finding a ride through from before the changes to see the difference, but I don't remember the London scene being notably different before 2015 (though I did find a Disney video talking about the 2015 changes and specifically mentioning a few changes to the London scene). What did they change for the worse?
I also prefer the WDW London scene with more dimensional buildings. I've always thought that the DL scene was much more limited and lackluster by comparison, but clearly WDI disagrees with me because Tokyo's PPF used to be identical to WDW's, but then had a refurb in the mid-10s and came back with a less dimensional London scene (among other changes) that brought the ride closer to DL's. So enthusiasm for lackluster London is currently in at Imagineering for reasons beyond me, and even Shanghai's version is like that now. Undoubtedly WDW's dimensional London would leave if the ride ever got the comprehensive refurb it desperately needs.
There are things there to be jealous of, and things I miss every time I go to DLR (what I would give for Liberty Tree Tavern and the WDW Haunted Mansion to both be in California!), but unfortunately you were not able to see them due to time, circumstance, etc. There's plenty of flaws at WDW that aren't at all hard to see, and all are legitimate, but it really is about the sum of its parts and taking it in as a whole experience in a way that DLR isn't, whereas in California, Disneyland the park is an experience but the resort itself is much more tenuously held together IMO. At WDW it's the opposite.
Animal Kingdom and Kilimanjaro Safaris are fantastic. There's still a lot of old school WED weirdness in the older corners of the property, nice hotels that are worth exploring, lovely restaurants (and a lot of them) either in theme or cuisine that DLR has little equivalent for, the original Tower of Terror is still one of the best theme park attractions ever made, the water parks are lovely, World Showcase is a fun area just to explore, etc.
But it takes time and mindset. My first time back at WDW as an adult was a family trip with my grandparents and cousins. As one example, my grandparents and I split up parts of two days exploring World Showcase, doing each attraction, going through each shop, taking in the atmosphere and acts; by contrast, my cousins (also from California, haha) went around the whole lagoon and "saw World Showcase" in less than two hours. We 100% got more out of the experience than they did because we were open to WDW on its terms, and they simply were not. Naturally by the end of the trip my grandparents, who hadn't even wanted to go to WDW, ended up having more fun than my cousins, who just wanted to blitz through the highlights in three days so they could say they had "done" WDW (but also wanted to sleep in, etc). My conclusion from this experience, reinforced through at least a decade of trip reports on this site or that, etc. was that people can't sprint through WDW AND appreciate it properly at the same time. I'm sure on occasion it can happen, but experience and a lot of internet reading has shown it to be quite rare if it does.
I'm just thrilled to be here safe and sound, and by a fire pit with a glass of my Aunt Ingrid's famous Swedish Glog she always served at Christmas.
