Too much water overall - Hoenn has many surfing routes and it takes forever to travel to places like Pacifidlog Town. Also, Hoenn has lots of water type Pokemon and the final gym leader in RSE has water types. You'd struggle without a good grass or electric type Pokemon on your team.
Lack of...
Bertha cuz she's very friendly and her team is quite challenging. Also, she congrats you for working together with your Pokémon to win after beating her.
I like Celadon City the most cuz it has a department store, condominiums, and a game corner. Plus you can get a free Eevee! You can even buy stones there to evolve it.
My favorite is Roxanne cuz she's an honors student and graduated from the Trainer's School. I also like Tate and Liza cuz they're super cute and are the first gym leaders to have double battles. I really admire Norman as well cuz it's great to face your dad in the game. Oh, and Flannery looks...
My favorite is Jasmine cuz she makes an appearance in Sinnoh and takes good care of the Ampharos in the lighthouse. She's very bashful yet kind. I also like Morty cuz he's cool and mystical.
I liked Soaring the most, it's breathtaking to see the Hoenn region from above. Also, I think the Delta Episode is awesome. The Contests in Hoenn were great too.
I like many features in Gen 6 like Pokémon Amie, Mega Evolutions, Fairy types, and Trainer Customization. Also, I like that the EXP Share became an item, it helps me with training my team.
I like all these features, though my favorite is the Battle Frontier. The battle facilities were fun and challenging, but not as ridiculously hard as the Battle Frontier in Gen 3. Plus the Frontier Brain theme is totally awesome! I also like the Distortion World for its cool angles. The Super...
I honestly don't like many features in Gen 5. The only thing I really loved in Gen 5 that wasn't in previous games is the infinite TM use. Though the Season Cycle and PWT were pretty cool.