Wouldn't those old stories be "more" official in a way, because at least Lucas was apparently actually reading those comics and semi-involved back then? He was handpicking specific artists, and voiced his displeasure at the first marvel story (the one with the big green rabbit) and a completely new writer and artist took over...
Either way, this cartoon looks kinda cheap. It will really be interesting to see how this does in the theater. Without the "regular" movie audience we might see theatres with a weird mix of 10 year old boys and schlubby grown men, and nothing else!