No matter what was done with Diamond/Pearl remakes, I couldn't see people not complaining. (And by that, I mean more than usual. :P) I didn't see a way to stay faithful without keeping the grid and I didn't see how they'd keep the grid with high quality graphics. Apparently, neither did Game Freak. I don't mean that in a bad way though, I like it.
The other major thing is the Sinnoh Dex. They could do the unextended Dex to avoid complaints about being "unfaithful" to the original games, but sticking to that and not using the much better Platinum Dex would suck. Seriously, they need the Platinum Dex and when I say "need" I mean, "I'm the kind of fan that goes with whatever and throws my money at Game Freak, but not doing the Platinum Dex would make me not buy Brilliant Diamond." I don't need to explain it because everyone knows about the joke that is Flint the Fire type Elite Four, but I'm still going to say it just for the sake of someone saying how bad it is. The Ice Gym Leader has 4 Pokemon. Only 3 are Ice types and she's only able to use 3 because she uses both Snover and Abomasnow. Literally every trainer in the gym either has just a a Snover or at least one Pokemon that isn't an Ice type. There's one trainer that even uses a team of Pelipper, Golduck, and Steelix! The Electric Gym Leader uses 2 Non-Electric types and Flint of the Elite Four uses every Fire type in the region, Infernape and Rapidash. That's it. Two. Including the starter. The rest of his team is Steelix because of Fire Fang, Drifblim because of Will-O-Wisp, and Lopunny because of Fire Punch.
Thankfully, Porygon-Z hints that they're using the Platinum Dex. I'm optimistic about these games even though it only took a few seconds for my first complaint, (Aww... People still have oversized heads.) but then again, I'm not asking for much. My main complaint so far that the names are kind of... boring. It's just describing the gems, not the box Pokemon. (que more arguments about HGSS about if Heart and Soul describe Ho-oh and Lugia...)
Side notes: Palkia and Dialga don't have new form, but they didn't need them unless Game Freak likes breaking Ubers.
Between no Dynamax and the art style, I think SwSh will stay the "main" games. It's going to be nice to not have to transfer all my Pokemon to a new main game.