Generation V may have had an actually good story, but the pokemon designs were... eh. Consider the
ice cream cone pokemon, the
garbage pokemon, the admittedly cute
gear cog pokemon with a strange naming pattern, the
ugly stunfisk, the
really odd toad and
whatever the hell mushroom pokeball pokemon this is. I always thought Darmitan looks odd too.
Admittedly, there are a few good gen V pokemon designs.
Chandelure looks great, even if it would look better placed as a heartless in Kingdom Hearts. But Gen V does continue the trend of boring Fire/Fighting starters. It was fine for one repeat in Gen IV with Chimchar (if only because Infernape looks cool) but they dropped the ball with Tepig, whose final evolution looks ridiculous. Thank goodness Gen VI changed things around with Fire/Psychic.
I don't know. Gen V's pokemon for me didn't always feel... like pokemon. Some of them are just visually unappealing, or it feel like they were trying to hard to make up the numbers. They did introduce
a lot of pokemon in that Gen. It just didn't look natural, at times. But the story is very good. I'll give it that.
Gen IV gets quite a lot of hate. I don't know. It wasn't 'groundbreaking' but it didn't do a lot of things wrong, either. It was a solid, if safe, generation of games, which also gave us remakes of Gen II, which is nice. The pokemon designs are fine, if reminiscent of Gen I at times. Starly is basically a different pidgey.
Gen III had some of the most borked designs. Most of the legendaries look really CGI. Groudon just looks bizzare and blocky to me. There was also a ton of water in this generation, which is a marked change. They removed the day/night cycle, which felt somewhat of a backtrack. I don't know, Gen III didn't catch me.
I'll have to go with Gen II, though, for improving on what Gen I lay, and for giving us a fantastic post-game journey through Kanto.