I disagree on 2 being the best, but it's still top-tier. I'm impressed Kanto was fit into the game, but the region is pretty empty with not a lot happening beside the gyms. It's alright for post-game, but it still seems underwhelming coming after a game with said region having more content there. I also like that gen 2 allowed full backwards compatibility with the previous games allowing for trading forward and backward between generations. Every game since has been a one-way transfer. (Even with Bank, which I thought could at least allow inter-gen trading with supported games. Glad I never paid for it.)
>Breeding brought forth baby Pokemon
Breeding was one of the best additions to the series, while baby Pokémon was one of the most pointless.
>I adore the aesthetics of gen 2
>the very traditionally Japanese setting differentiates Johto from Kanto (and every subsequent region in that manner) and contributes a lot to the game's aesthetic appeal.
Same. I wish more games focused on proper setting themes. Gen 1 was fine for being basic considering the limitations, the scope of the game, and it was the first in the series.
Gen 3 really didn't take advantage of the tropical setting as much as it should have. I liked Fortree City and Pacifilog Town, but nothing else seemed as creative as far as building designs. At least overworld theming improved with added weather effects.
Gen 4 had the vents scattered around for the Underground (subtle and not really as remarkable, but it was a nice touch). More cities had distinct functions and looks to them compared to previous games (coal mining, industrial port, marshland, snow resort, etc), but the buildings could have been better designed to belong there.