>>52875427Johto will always seem fresh to me. Years down the line and out of all the pokemon in the entire franchise, Johto seems to have hit this perfect mix of weird and out of place, but with endearing and cool qualities to its batch of pokemon. The only other gen I can think of that almost captured that feel, but veered a bit too much on making some lines goofy, was Unova.
Kalos was sort of the tipping point where it still had solid designs that felt unique to the franchise. Everything after Alola feels like Pokemon were designed trying to follow trends or competitors. Kanto feels like a product of its time, Hoenn works as a mix of the previous installments, and Sinnoh sort of had a similar design philosophy to Johto, but managed to work it out differently with cross-evolutions and the like.