I completely agree with you... the Jungle Cruise is the best attraction as far as themeing and design.I've been to Anaheim, Tokyo, and Orlando.
I found Disneyland to have the strongest theming, when compared only to The Magic Kingdom and Tokyo Disneyland. I found the different lands in Tokyo were not well separated and distinct. The Magic Kingdom is comparable, but has less lands, and lacks Disneyland's intimate charm. Some of the newer parks like Animal Kingdom and DisneySea have more immersive theming, but it's kind of comparing apples to oranges.
Disneyland has the best collection of attractions in any one Disney theme park. I think that DisneyWorld as a whole is the greater experience, but no individual park there comes close to Disneyland. The Magic Kingdom's Fantasyland in particular, pales in comparison in terms of number of attractions. Using Disneyland as the standard bearer of how many attractions a Disney park should have, DisneyWorld kind of feels like they've the attractions of two or three parks and stretched them out over four parks.
Disneyland still boasts Indiana Jones, one of the best Disney attractions in existence (it's a crime they haven't topped it in the ten years since, but I digress). One of the newest rides, Expedition Everest, is impressive but is not as epic as Indy. And the addition of that ride doesn't make Animal Kingdom even come close to be being the park Disneyland is. Now, if only they'd Pooh's Hunny Hunt in Anaheim. That's a big point in favour of Tokyo Disneyland.
So for me, Disneyland is the best park, based on my personal priority of attractions & theming. It's definately a personal opinion as to what matter most to the individual, so I don't think any of us can definitively declare any park to be "the best".