It's certainly an odd choice to have a new female character instead of revamping Crystal, but I suppose if you go by the logic of these being G/S remakes instead of Generation 2 remakes, it fits because G/S didn't have their own female character, and Crystal the character fit a bit more with Crystal the game's theme, most likely because of her hair (and actually, most of her sprite was blue, too). That said, I don't think her design is too bad, although the first few times I looked at her, I kept getting a Leaf vibe from her. The new Gold looks awesome, as well, and it'll be great to play as him again. XD
The new Sugimori arts are cool, as well. Wooper's got a really nice "oh?" expression on its face, and Mareep and Chinchou are great, Chinchou looking like it's going for some action. Blissey's is great, too, and Miltank isn't too bad, although those bad Whitney memories are still intact, lol.
It was also nice seeing some of the Sprout Tower and Azalea Town. I always liked those first-person views in FRLG of the place you just entered, even if they were a bit repetitive, but here, it looks like some real work went into making them. For a FPV, that Sprout Tower looks awesome. As for Azalea's Slowpoke Well, seems they opted to make it a bit harder to get to by literally making it a well, which I don't mind. As a well, it should be at a lower ground level than the rest of the map. Also liked how Ilex Forest now looks, and that shrine looks great.
As for the starters following the player, I don't really mind it too much, but I hope that they give us the option to use that ability.