If you talk to the Game Freak Director in HGSS he says that remaking an old game for the present time is a challenge since it has the appease the fans of the original while "not doing the same thing over again". To bring back memories while creating a new experience.Actually I think the more target audience are those who never played Gen 4 before. I get the feeling from FRLG, HGSS, and ORAS that they wanted those games to appease/entertain/surprise both veteran players and new players alike.
I don't get that from BDSP either, Granted, it's another dev team but the director is from GF...
Regardless, ILCA must be included in the 'obligatory Game Freak building' and hopefully some words about finally outsourcing after so many years lol