All the pokémon from R/B/Y & G/S/C were already available before the remakes were released, players could pick up the Kanto starters in other games (Colloseum for example) that were released on other consoles. I know for a fact that no new pokémon were released in HG/SS as my LeafGreen pokédex was fully completed years before Soul Silver was release.
I am SO hoping for Ruby & Sapphire remakes, the Hoenn games are by far my favourite of any pokémon!! If there had to be a good reason, I'd have to say it was down to the sheer amount of things to do outside of just battling... making a good battling set & a good Contest set was a great challenge. Let's not forget the pokémon it gave us, Wingull, Blaziken, Gardevoir and let us not forget the glory that is SECRET BASES!!!!!!!
I think it's finally time for Ruby & Sapphire to return now that pokémon has arrived on 3DS, finally Gamefreak have the power to make the game as it really should be made, deep, rich and revolutionary!