I think HGSS did the best job as remakes.
-It had the most additional content of the remakes between the Johto Safari Zone, Gym Leader and E4 rematches, following Pokemon, Pokeathlon, Platinum's Battle Frontier, Pokewalker, and probably a few other features that I'm forgetting right now.
-It kept the Suicune storyline from Crystal. This is a point it has over ORAS, which didn't include Emerald's Battle Frontier, Desert Underpass, etc.
-It improved on the Kanto region by putting in Viridian Forest, which I remember was a common criticism of the original GSC. It also gave more characterization to both the Kanto and Johto leaders through interactions outside their gyms.
ORAS comes in second for the additional Pokenav features, Soaring, expansion of Team Aqua and Magma's goals (and making the leaders and admins have their own personalities as opposed to the originals where Archie/Maxie, Shelly/Courtney, and Matt/Tabitha were basically carbon copies of each other), and the additions to contests and secret bases. FRLG is third, not because I didn't like them, just because they had the least amount of new content, etc. That's to be expected though since FRLG were the first remakes of the series, and they were remakes of the first games.