I seriously hope that the green used in those D/P screenshots isn't the actual color used in the games, since that is a very bright green. Looks rather unnatural; while I don't hate it, I far prefer the color used in the R/S games. Though it seems like the color contrast is rather high on those shots, so it possibly could be different.
As for the starter triangle, I doubt they'd change it not only because it's "tradition", but also because there's no other type triangle (that I'm aware of) that works in the same exact way when it comes to resistances and weaknesses - that is, each type is weak to one type in the triangle and resists another. I was thinking about it some time before, and I realized that the only other triangle that comes the closest to how things currently work is Rock/Flying/Fighting - however, since all starters (except for Pikachu) seem to start with normal-type attacks, a rock-type starter would already have a distinct (and rather unfair) advantage at the very beginning of the game. So that's out as well.
Any other triangles either feature an immunity somewhere instead of a resistance, or are "incomplete" (one or more types don't resist any of the other types).