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Why do people say Gen 6 was the downfall?
>Gym Leaders using 3 Pokémon
Started in Gen 5
>Elite Four using 4 Pokémon
Started in Gen 5
>Focus on the characters and story rather than your own adventure
Started in Gen 4
>Linear gameplay
Started in Gen 4
>Excessive handholding
Started in Gen 4
>Linear region
Started in Gen 5
>Theme pack region with no identity
Started in Gen 5
>Roadblocks after every story advancement
Started in Gen 5
>Simple route design
Started in Gen 5
>No postgame
Started in Gen 5
Seems to me like Gen 4/5 was the beginning of the downfall (with a brief peak at HGSS).
Gens 1-3 + LA is "true Pokémon".