Ah, man, this is a toughie for me. Emerald was my first game, and I never owned Ruby or Sapphire. I don't think I had a strong opinion one way or the other about either of them back then, and I don't even remember knowing that Steven was the champion in the other games.
Through playing Alpha Sapphire, though, what with the amazing redesigns, the 3D character models, and the cinematic cutscenes, I've come to really like Steven as a character. It sort of helped that RS/ORAS had such a big emphasis on him in the story, and yeah, it was an odd, different experience not having Wallace as the champion, but from going through AS' story and seeing Steven every so often, it felt very fitting and satisfying to fight him as the Champion. I really love his dialogue and personality; he's become one of my favorite Pokémon characters. I also really love how they took his character and role in the story from the originals and tied it in cleverly with Mega Evolution, the Mega Stones, and other things introduced in X and Y.
And yeah, it was nice to still see Wallace redesigned and also be able to battle him. I like that they gave him some backstory and lore about being a member of the ancient Sootopolitan people (I like that he has a story-centered battle outside of the Gym match, they should do that more often, gives the leaders a lot more character :D). But in the end, I'm not upset at all that it was the Wallace I remember from 10 years ago, I became very fond of Steven, and was really happy with his role in the game.
Overall, I really like both, but I like Steven more as a character, but I assume this is specifically about RSE instead of both that an ORAS, isn't it? ^^; If that is the case, then I'd say I like Wallace more, as I remember much more of him from Emerald than Steven.
