I can prove they have stopped using quite a bit of tradition in the screenshots. For instance, they gave Brendan actual hair, which is necessary for customization. If they were going classic, there would be no hair. They went classic style with Gold in HGSS so why didn't they make Brendan that way now?
Next, this is unrelated but they put in all 9 Sinnoh forms in the pokedex unlike HGSS where they only put 5/22 forms because of ancient power evolution. They were hooked on tradition when it came to HGSS and FRLG where it made no sense when you couldn't get a Crobat in the main game. I can see that its almost confirmed that the Hoenn pokedex is expanded.
Oh yeah and starting in ORAS, all gyms, centers, and marts have icon signage. I'm trying to figure out all three icons on the pokemarts. One is surely a pokeball, another is likely a potion, now I wanna figure out the last icon.