It's allowed fans to get their hands on the rarest of all Pokemon reasonably early in their adventures, to play through the whole game with them. However, with Pokemon Legends: Arceus' rewards for previous games already announced, it certainly seems like players of this game will be getting a better deal than those of Brilliant Diamond and Shining Pearl.
Starting with the game that's already out, Brilliant Diamond and Shining Pearl got two major rewards for previous games. The one players got for having a Sword and Shield save file on their Switch is the Mythical Wish Pokemon, Jirachi. The last time Jirachi was distributed as a free perk was in 2018 with Pokemon X and Y, and even then, it was only in Japan. Western players who wanted a Jirachi had to have been around during the 20th Anniversary distributions in 2016 to get one.
With it being five years since most players could receive a Jirachi, having a method to reliably catch mythical Pokemon forever is nice for future players. Jirachi's rarity means that players will never have been able to play through a campaign with one before, too. This is what makes the Pokemon's placement in Floroama Town so great. Players will reach this area just after getting their first Gym Badge from Roark, so it can slot onto their growing team easily if they wish to travel the region with it.
Before getting to the main event, players of Sword & Shield will be getting two rewards in Pokemon Legends: Arceus, instantly giving it an advantage over the Sinnoh games. The second reward is an outfit, taking advantage of Legends' full trainer customization, as opposed to Brilliant Diamond and Shining Pearl's limited dressing options. This is a unique kimono set featuring Shaymin's color scheme, along with some nice texturing, making the outfit feel light, grassy, and very stylish.
The big one, though, is Shaymin themselves. This Mythical Pokemon has long been a fan favorite, but isn't often featured very highly by the Pokemon Company. Like Jirachi, the last Western distribution for Shaymin was in 2016, during the 20th Anniversary event. However, Shaymin was briefly available in Brilliant Diamond and Shining Pearl through the use of a glitch that has since been patched. Those who either missed out on this glitch or didn't want to use it will be pleased to get a legitimate Shaymin very soon.
However, the fact that Shaymin and fellow Mythical Pokemon, Darkrai, are programmed into Brilliant Diamond and Shining Pearl raises some eyebrows. It turns out these Pokemon may not be exclusive to Pokemon Legends for very long, as the events from the original Sinnoh games could soon be coming to the remakes as well. With an additional method to get these Mythical Pokemon, the rewards Legends offers players may not be so special after all.
While the Sword & Shield rewards are the most prominently featured, it is worth noting that both Brilliant Diamond and Shining Pearl and Pokemon Legends: Arceus have announced rewards for the other Nintendo Switch Pokemon games that released before them.
Starting with Let's Go Pikachu and Let's Go Eevee, it seems like Brilliant Diamond and Shining Pearl got the best deal here, as players with those save files will be able to get a Mew in Floroama Town at the same time as Jirachi. Sword & Shield's rewards were pretty good, too, giving access to a Gigantamax Pikachu and Gigantamax Eevee, two Pokemon which have been scarcely available through any other method since the game's launch. Finally, there's Pokemon Legends: Arceus, which got the short end of the stick, just offering the cosmetic masks, with Pikachu or Eevee-themed faces.
That leaves one major reward that was recently announced for Pokemon Legends: Arceus, which for many players is by far the most exciting yet. Those with a Brilliant Diamond and Shining Pearl save file will be able to get Darkrai, and a nice set of Team Galactic clothing while they're at it. Darkrai has long been a fan-favourite Mythical Pokemon, being the subject of one of the most beloved anime movies in the Pokemon franchise. It has also been revealed that this will be part of a postgame story event, too, so there's more intrigue in it than just being handed the Pokemon.
This is clearly a habit that will continue into the future of the franchise, so it leaves fans speculating what rewards might come around in the next Pokemon games. Be it Generation 9, "Let's Go! Johto," or something completely new, the previous games will have some rewards in-store for long-time players. The obvious first step is Pokemon Legends: Arceus allowing access to Arceus itself. Game Freak may not want to do this, though, depending on whether or not Arceus will be catchable in Pokemon Legends. If this is the case, they could instead give the "Plate" items that allow Arceus to change type.
There are still plenty of Mythical Pokemon that haven't been available to Western audiences in years. Victini, Genesect, and Hoopa, just to name a few, haven't been available since 2016. When Generation 9 eventually rolls around, fans' desire for Black and White remakes will no doubt start to surface, so pushing these Mythical Pokemon might satisfy their desires for a while. Regardless, it's comforting to know that Game Freak and Nintendo are always looking to reward players who have stuck by the franchise for a long time.
Pokemon Legends: Arceus will release on January 28, 2022, for Nintendo Switch.