>>39534288Gen 3 had the coolest aesthetic/design, the best legendaries, and around gen 4 was when Ken Sugimori started running out of ideas and the pokemon designs started going a bit off the rails, especially after he completely let go of creative control in the two most recent generations.
Hoenn is the best and most colourful region, has the most upbeat storyline, a decently hard rival, and Emerald improved on Ruby and Sapphire with the Battle Frontier, which is probably the only legitimately challenging part of any pokemon game besides completing the pokedex, which is more luck than skill. The cloning glitch was also great. Emerald is a masterpiece all around.