>>58410864>>Emerald>Vastly improved storyNo, not really, it's pretty much the same story except both teams are the bad guys, you only get slightly more interactions with both of them, and their teams were practically interchangeable anyway (it's just Numel/Camerupt vs Carvanha/Sharpedo). Maxie and Archie still walk away scot free
>Slightly improved spritesI'd argue that giving animations to all 386 Pokémon and forms was pretty significant. Sprites for items too, but that was a FRLG addition. Doesn't change that most overworld sprites are still just placeholders of Gen II Trainer designs. Some of the Trainer sprite alterations seem superfluous.
>>Platinum>Greatly expanded regional PokédexYou say this but it's just moving 56 Pokémon from post-League to pre-League. Platinum only adds 9 new Pokémon to Gen IV, 3 of them being to the regional Pokédex. Making the starter something that's given on Route 201 doesn't make the game better if it means you're no longer getting it at Lake Verity. I also don't like Platinum's Gym progression. It's more linear and boring and they make the world railroad you to accomplish it while not even changing the order of the badges in the badge case. Fantina's Gym puzzle is better in Platinum though.
>Improved sprites and character designsThe poses are a bit more dynamic, but I wouldn't call the spritework better. Base games are supposed to present the Pokémon in a standard state while third versions have to liven them up a bit. Lucas, Dawn, and Barry are the only updated character designs, and I wouldn't call Dawn or Barry's outright improvements, they're just different.