>>42558465While they added some amazing things (Safari Zone, Pokeathlon, Gym Leader / Elite 4 Rematches, many new Legendaries, Hoenn / Sinnoh Sounds, Pokemon following the trainer, improved Kanto areas, Battle Frontier, Wi Fi Plaza), they also made many things a chore and heavily more annoying than they originally were (Lyra / Ethan interruptions, Kimono Girls storylines, forced tutorials, forced Lugia / Ho-Oh encounter, Gym Leader rematches preparations, Safari Zone's new mechanics) and they even removed small things like room customization, and kept many GSC problems intact like the level curve, the emptiness of both regions (outside of Safari Zone and Battle Frontier), Pokemon distribution and cheap Team Rocket.
Overall, they are pretty good games, but the pacing, dialogues, UI and present problems from both gen II and IV make them not as perfect as people usually claim they are. They aren't the ultimate way to experience Johto as Crystal is also a thing, butt it sure is worth it.
