https://www.youtube.com/watch?v=BdAMOFTwkVMI played UM for the first time only a couple weeks ago, but there is something vaguely nostalgic-feeling about Iki Town and the first island in general. IDK what it is
Might just be because aesthetically the game is excellent. Even if the gameplay itself was lacking, the region was gorgeous, the music was nice, the dex fit the setting really well, and it actually had some really loveable characters (which is rare in Pokemon games for certain, XY's cast was especially insufferable)
Maybe it has something to do with it feeling like my 'last' Pokemon game. Since I only recently got Citra working to play it, and I have no plans on playing SWSH, in some ways it was the conclusion to my journey.
I suppose if you look at it like that, some of the Kanto references and callbacks could be seen less as pandering and just as a way of bringing things full circle before putting the franchise to rest. Pretending it's the last Pokemon game certainly works for me