These games are great, but there's one thing I don't like about them. It's the fact that they put too much emphasis on going back to Kanto, and Kanto Pokémon in general.
I really enjoy the setting of Johto, it has a very Japanese feeling to it and the landmarks are kino. That said, I wish the actual region was longer and the Elite Four was more challenging. It feels like they watered down the Johto experience just to compensate Kanto, but the problem there is that it's not fun revisiting Kanto like it was in the original RBY. All I remember doing is battling the gym leaders and waking up Snorlax. The rest just felt empty and like a chore. I played Gold again recently and I had a lot of fun until after I beat the Elite Four, where I just really couldn't continue any more because Kanto is so boring in this game. It is better in HGSS since they opened up things that were shut in GSC such as Viridian Forest. The inclusion of Kanto is really impressive as a technical achievement but personally I think it's overrated because it hampered the new region's experience. It's also a great insult to Johto when people say GSCHGSS are great because you get to go to Kanto, as if that's the main selling point...