For one, many of the Pokémon that have been shown off in the game’s trailers are absent. In fact, on launch day, only around 180 'mons are actually programmed into the game. Now, we knew not every Pocket Monster would be available, but fewer than 200 is a bit of a surprise
Pokopia is a silly spin-off that would have been an automatic success on IP alone. It has 300 pokémon at launch, runs great, has loads of content and custom animations and feels very alive with many real-time, interactive elements.
Meanwhile the game built around the series’ minimal core mechanics apparently runs like shit, has about half as many characters as Pokopia and not even a fifth of the total roster, and doesn’t even implement correctly the simple established rules of a turn-based RPG battle.