Summary
Pokemongames constantly introduce new elements or change older ones in order to keep the series' classic formula as fresh as possible with every release, and a big part of this is the pocket monsters themselves. Adding new Pokemon to mix and match things up works extremely well, especially in modern games where not every existing critter is brought back, and some may need some competition for their respective niches. For example, with Aegislash not being in Gen 9, it made sense to add a new Steel/Ghost Pokemon like Gholdengo. As such, there are 12 Pokemon that put Game Freak in a rough spot because they either need a “replacement,” or they need to come back inPokemonGen 10 games.
It’s never easy to balance video games to the point that players have everything they might need without making it hard to have healthy meta and competitive formats. This is especially true forPokemongames, and Gen 9 proved just as much. While creatures like Paradox Pokemon fromScarlet and Violetare unique and fun gimmicks, they can be polarizing and just a bit too strong in some cases, warranting for next games to skip their inclusion. What follows is that some Pokemon with unique Abilities that enable playstyles should always be included to some degree, and that comprises weather and terrain setters.

Pokemon Gen 10 Must Bring Back Terrain and Weather Setters or Replace Them
There are currently 17 Pokemon in the series with Abilities that directly create various terrains or weather conditions, but many of them end up rarely being available in competitive formats - especially early on. Likewise, these critters may be hard to come by in the wilds, if at all, and one might need to usePokemon Home’s transfer functionto bring them over to their game. Not counting Legendary Pokemon and other exceptions, the list includes 12 Pokemon that can create terrain or set weather up just by entering the field.
Aside fromPokemon Scarlet and Violet’s Miraidon, which is not guaranteed to be available at all in Gen 10, there are currently fourPokemon whose Abilities create a terrainwhen entering the battlefield. These include:

There is a notable exception to this list in the form ofPokemon Scarlet and Violet’s Arboliva. This tree-like Pokemon has the Ability Seed Sower, which creates Grassy Terrain whenever it’s hit, which is a valuable tool for players to have when Rillaboom is not around - much like at the beginning of Gen 9. This Ability shows that Game Freak can use known gimmicks with unique twists to “replace” some Pokemon that would otherwise gut their niche if removed, and Rillaboom from Gen 8 was one of them.
Notably, be it through Tera Raids or DLC, all terrain setters came back to Pokemon Scarlet and Violet - albeit Galarian Weezing is not natively available in Gen 9 and must be transferred from Pokemon Home.

In the same situation are weather-setting Pokemon. Aside from Koraidon, Groudon, and Kyogre, the list includes:
This category includes two Pokemon per weather type, which is great for offering more options to players who like to build around weather conditions, and it also means it’s likely at least one per category will be brought back in Gen 10 and beyond.PokemonGen 10 games can always add newweather-setting Pokemonto their roster, but if not, then they are forced to bring back at least one per category. This is the ultimate conundrum:PokemonGen 10 can’t leave these 12 Pokemon behind unless new ones with equal or similar Abilities are introduced, and the reason is that they enable their respective playstyles - which Game Freak can’t ignore.

Pokemon Scarlet and Violet
WHERE TO PLAY
The school that you’ve enrolled in as you playPokémon ScarletandPokémon Violethosts a special independent study project. The theme of this assignment is “A Treasure Hunt.” Explore the world and seek out your very own treasure!Three stories will be woven into your adventure while traversing the sprawling Paldea region. Along Victory Road, you will go to Gyms in different locations in order to to achieve Champion Rank. On the Path of Legends, you can join Arven in search of rare ingredients. And in ★ Starfall Street ★, you’ll challenge Team Star, a group of delinquents causing trouble for the school.These stories are set in an open world, so where you go is all up to you. A world teeming with Pokémon and people to meet is waiting for you—traverse the Paldea region wherever you heart desires.





