You know they'll probably get handed source codes from gamefreak or at least some very streamlined guidelines on how the gameplay should be, right? since they been doing it for 25 years...
Just because it's not developed by GF doesn't mean they'll struggle. If they can code the whole game and battle system, adding megas is no big deal. Why would you think adding mega mechanics would be so difficult for a studio that's gonna develop an AAA game for gamefreak?
just mean they cant just change stuff because they want to, when your an outside studio doing work for the big guys you get a timeline and a budget and you dont get paid extra if you put more stuff in, than what the employers asked you too, and timelines are already tight enough to make games and they get paid the same if they add megas or not since if gf didnt explicit said to include them, they wont go around saying hey gf let us put megas becuase we want too...
Also a remaster/remake is not an AAA game material speiclay when they do it like they are doing it where its just a gfx overhaul and not a remake that is totaly diferent like resident evil 2 and so on.
Also you do know this studio is a
SUPPORT Studio and has no games in the catalog right? they are mostly an helping studio that does minor stuff like cgi and afew codding for minor stuff and so on, they never outright deevelopped an game as the main studio unless you count pokemon home which isnt even a game but an app to store pokemons.
"
What other games has it worked on?
As we
previously mentioned, ILCA is a support studio. As a result, it's worked on all sorts of games including regular ones, augmented reality titles, virtual reality games, and various other stuff including a Domino's pizza app featuring
Hatsune Miku."
they basicaly have no track record of being main developers, they just outright do minor codding, cutscenes, cgi stuff.
Also did you read what they said about the game
"Pokémon Brilliant Diamond and
Pokémon Shining Pearl enable fans to experience the original story and game features from
Pokémon Diamond and
Pokémon Pearl in a fresh way. The original games have been faithfully reproduced and colourfully revitalized for Nintendo Switch.
"The sense of scale of the towns and routes has been carefully preserved, and fans who played the original games will recognize many familiar places. These games are updated with the easy-to-understand, player-friendly conveniences introduced in recent Pokémon core series video games, in addition to up-close-and-personal Pokémon battle scenes."
just looking at "faithful remake" and "preserving routes scales and areas to be imidiatly recognizable", just screams they are gonna 3d the spirits and call it a day.