The way Pokémon Brilliant Diamond & Shining Pearl handle Ditto is a refreshing turn for the series. Ditto has always been best Pokémon to place in the Day Care, as it can breed with any other species and thus facilitate producing competitively viable Pokémon as well as completing the Pokédex. However, having a Pokémon that makes the game as easy as Ditto does is not always a good thing.
Fans of the series have complained that recent Pokémon games have been easier than older. Between locked Exp.
Read more on screenrant.com