TLDR: This game is perfectly fine as a Pokémon game especially if you never played the originals but as someone who has it leaves a lot to be desired in some areas.
This game is kind of a mixed bag. Its probably the most fun I have had with a main line Pokémon game in a couple years but that wasn't hard to do after lets go and swsh. Fundamentally the game is fine. It looks fine, runs fine, and plays fine. Its a normal Pokémon experience but as someone who played the originals and has been playing since gen 3 there are certain aspects that I wish was done better. I suppose to start any improvements or new features made by platinum were gutted in the remake. No expanded regional dex, no distortion world, etc. "But its a remake of diamond and pearl not platinum" to that I say look at Heart Gold and Soul Silver. A remake of Gold and silver but also included elements of Crystal and added brand new areas off the beaten path to explore and have new encounters. It was less of a remake of Gold and Silver and more of a remake of the Johto region and I feel that's how remakes should be done for Pokémon and that's what should have happened with Brilliant Diamond and Shining Pearl. Platinum elements could have been added to make this game the definitive version of Sinnoh.
Secondly this game is missing the National Dex kind of. This game features every Pokemon that was programed into the game as of Gen 4 but nothing beyond that so no evolving your Eevee into Sylveon and no catching and transferring anything beyond Gen 4. This in my opinion is dumb. It was dumb when they did it in swsh and its dumb now. They have been using the same models since xy they can fit every pokemon into the game. They can't say its for balancing the regional dex because they solved that issue back in the day in Firered and Leafgreen which were remakes the the very first games. In those games you could only use the original 151 but once you beat the game the rest were unlocked. Golbat is a good example of how this worked as you couldn't get Crobat until you beat the game but once you did he became available. Now your game has a similar feel and play to the original but opens up more once the game has been beaten. They could have done that here but chose not too. I am not asking for every Pokémon to be catchable in this game just I am asking for every Pokémon to be programed into the game so that way if they are not catchable they can be transferred in from Pokémon Home. It absolutely baffles me why they don't even do that now. Keep whoever you want catchable in the game sure but whoever isn't should be transferable in. Sun and Moon did not have a National Dex just like swsh but whoever wasn't catchable you could transfer in from Pokémon bank and it would be just fine. The idea that a game on the switch can't handle all the Pokémon is just dumb when a 3ds game can and the switch uses the same Pokémon models from the 3ds.
My complaints for this game come from me knowing what could have been. To the average person this game is perfectly passable but as someone who knows the franchise it has been sad watching its decline. If you casually like Pokémon you will most likely enjoy this game because the actual game is solid just like it was back then but as a hardcore fan you notice smaller things that could have been and ways this game could have been even better and a true definitive version of the Sinnoh.
This game is kind of a mixed bag. Its probably the most fun I have had with a main line Pokémon game in a couple years but that wasn't hard to do after lets go and swsh. Fundamentally the game is fine. It looks fine, runs fine, and plays fine. Its a normal Pokémon experience but as someone who played the originals and has been playing since gen 3 there are certain aspects that I wish was done better. I suppose to start any improvements or new features made by platinum were gutted in the remake. No expanded regional dex, no distortion world, etc. "But its a remake of diamond and pearl not platinum" to that I say look at Heart Gold and Soul Silver. A remake of Gold and silver but also included elements of Crystal and added brand new areas off the beaten path to explore and have new encounters. It was less of a remake of Gold and Silver and more of a remake of the Johto region and I feel that's how remakes should be done for Pokémon and that's what should have happened with Brilliant Diamond and Shining Pearl. Platinum elements could have been added to make this game the definitive version of Sinnoh.
Secondly this game is missing the National Dex kind of. This game features every Pokemon that was programed into the game as of Gen 4 but nothing beyond that so no evolving your Eevee into Sylveon and no catching and transferring anything beyond Gen 4. This in my opinion is dumb. It was dumb when they did it in swsh and its dumb now. They have been using the same models since xy they can fit every pokemon into the game. They can't say its for balancing the regional dex because they solved that issue back in the day in Firered and Leafgreen which were remakes the the very first games. In those games you could only use the original 151 but once you beat the game the rest were unlocked. Golbat is a good example of how this worked as you couldn't get Crobat until you beat the game but once you did he became available. Now your game has a similar feel and play to the original but opens up more once the game has been beaten. They could have done that here but chose not too. I am not asking for every Pokémon to be catchable in this game just I am asking for every Pokémon to be programed into the game so that way if they are not catchable they can be transferred in from Pokémon Home. It absolutely baffles me why they don't even do that now. Keep whoever you want catchable in the game sure but whoever isn't should be transferable in. Sun and Moon did not have a National Dex just like swsh but whoever wasn't catchable you could transfer in from Pokémon bank and it would be just fine. The idea that a game on the switch can't handle all the Pokémon is just dumb when a 3ds game can and the switch uses the same Pokémon models from the 3ds.
My complaints for this game come from me knowing what could have been. To the average person this game is perfectly passable but as someone who knows the franchise it has been sad watching its decline. If you casually like Pokémon you will most likely enjoy this game because the actual game is solid just like it was back then but as a hardcore fan you notice smaller things that could have been and ways this game could have been even better and a true definitive version of the Sinnoh.