There's a lot of talk on the negatives of the latest Pokemon so let me straighten that out by asking which Gen did it worst?
Spoiler warning in effect, read at own risk.
Game Mechanics
Gen 1, I'm sorry but it's impossible to go back and play Gen 1 without feeling depressed
New Pokemon
Gen 9, sadly after looking through the list there are quite a high number of left field designs.
Legendary Pokemon
Gen 5, although close with Gen 8 but 5 made worst Pokemon movies.
Anime
Gen 5 was the worst, hated the extra characters and hated Cilan.
Gym Leaders
Gen 7's lack of Gym Leaders was it's biggest negative and I never really took to them that well.
Elite Four
Gen 8's lack of an Elite Four doesn't do it for me.
Champion
Gen 6, Diantha is dull and probably the least involved Champion I've ever seen.
Rival
Gen 8, he won't shut up, his name is stupid and is the worst part of the new game so far.
Starters
Gen 8, one of them becomes a FIFA mascot.
Evil Team
Gen 8's team is lazy.
Evil Plot
Gen 3's is still the dumbest evil plot.
World
Gen 5, based on the abundance of do nothing areas, not fixed until the sequel.
Player Character
Gen 5, again something that had to be fixed in the sequel.
Post Game
Gen 5, there really is very little to do.
Navigation
Gen 3 is probably the worst for navigation not to mention how irritating the random encounters are.
Shameless Money Grab
Gen 7 really didn't need a sequel.
Pokemon Professor
Gen 4, Rowan is probably the most forgettable.
Dumbest Plot Point
Gen 7, how to shoehorn in a legendary Pokemon no one cares about.
Difficulty
Gen 6, gave you three Starter Pokemon. There's holding your hand and there's out right taking a gun to a sword fight.
Overall Worst Game
Pokemon Black and White
They had to do everything in the sequel, including actually finishing the game.
