Maybe it's just my age, or bias driven by nostalgia, but I'm not a huge fan of recent Pokemon production - I feel the Pokemon creations themselves feel quite forced. But thinking back to Red/Blue days, and the OG Pokemon, that will always bring back good memories and nostalgia.
Pretty sure gen 1 is inherently better IP and it's not a nostalgia thing. The only Pokemon I played was half of Crystal on a jailbroken iPhone as a kid.