Different Pokémon games have their own varying levels of reputation, and Pokémon Black and White have gone through many ups and downs, from being hated to being considered classics. These reputations can change over time for any title, but even though Pokémon Black and White (as well as Black 2 and White 2) are beloved games now that are looked back on fondly, they were almost universally hated at their release.
Pokémon Platinum is an example of a Pokémon game that was both beloved at release and is still beloved to this day, but not all the games are so lucky. It had the good fortune to iterate on what Pokémon Diamond and Pearl got wrong by expanding the size of the Pokédex, adding more endgame features, and making quality-of-life improvements. Many fans look back fondly at Pokémon Platinum, as well as others like Heartgold and Soulsilver, while also having found them appealing on release.
And while Black and White are as fondly ed now, they had to earn that reputation the hard way. Elements of the games that are loved now used to be despised. Game Freak took risks with Pokémon Black and White, and the initial community reaction to those risks was less than delighted.
Pokémon Black & White Had Risks That Changed Things Up
The initial thing about Pokémon Black and White that displeased so many fans at first is that the Unova region had a completely new Pokédex of entirely new species. Not a single older Pokémon was able to be obtained until the player received the National Pokédex. Fans weren't happy about not being able to acquire their favorite Pokémon, and they instead were stuck with brand new species that they had no previous attachment or nostalgia towards. Some Pokémon species like Garbodor and Vanilluxe received a lot of flak from the community as being lazy Pokémon designs, and the Unova Pokédex caught a lot of criticism despite having some of the series' best designs, like Hydreigon, Volcarona, Zorua/Zoroark, Chandelure, and Haxorus. It also didn't help Black and White's case that they had the series' third Fire/Fighting-type starter in a row with Emboar.
Black and White also took a risk with the animations inside of battle. Instead of Pokémon having an animation at the beginning of battle, the Pokémon sprites are constantly moving, which ends up with Pokémon looking a bit choppy and pixelated, and seemed like a step backward in sprite design compared to Generation 4. Even though Black and White are loved today, the sprite design of the Pokémon could use a makeover, having both aged somewhat poorly and being a factor in the initial bad reception of the games.
Pokémon Black and White was arguably the first time in the history of the Pokémon franchise where Game Freak put a lot of heart and attention into the story. The plots of the Pokémon games have often been mediocre, but Gen 5 was a standout in this regard, and is a huge part of why Black and White are looked back on so fondly. Gen 5 was also the last time that Pokémon games had any real difficulty (they even featured a hard mode), and the bad reception of Gen 5 is one of the big reasons as to why Gen 6 (Pokémon X and Y) was so easy in comparison. Even though Black and White had a terrible reputation at their release, the fanbase eventually warmed up to them over time, and they have become some of the most beloved games of the Pokémon series.