First, do you really think BDSP will not have connectivity with SwSh? I ask because for the games to be compatible they'll likely have the same amount of Pokemon indexed for compatibility purposes. So likely this implies there will be data in the games for Rotom forms and Giratinas Origin form which werent introduced till Platinum.

Second, Platinum content. By virtue of my last statement there must be some amount of Platinum content however big or small. Now I do think its possible we'll actually get the Rotom event. It would actually be a lot more faithful to include the Rotom event than just adding a catalog book item to do so. Maybe we wont get the Distortion World sidequest? Maybe the Griseous Orb will just be lying there at Spear Pillar after you catch your cover legend like Adamant/Lustrous Orb were in the base games? Or at Turnback Cave? Or maybe we could get the Distortion World as a post-game episode ala Delta Episode to maintain a faithful singleplayer playthrough and still have extra content but I admit Im reaching here.

Also how will things like Pal Park be repurposed?

And finally while I dont think its likely that theyll add the Battle Frontier the Battle Tower already is a part of the base games. It shouldnt be too difficult or too unfaithful of they chose to implement it.

I just wanted to analyze the possibility that there will be more content to the games than just a simple faithful remake of the game. Hell even ORAS had Dexnav and other unique features. If the game was just Sinnoh alone and Sinnoh Pokemon with nothing else then I think many people are gonna be disappointed.