Vader should not be the main villain.
Vader will be the main villain. XD skews even younger than Cartoon Network. I'm sure we'll see plenty of additional villains, though.
Well I can't see him actually headlining the series as a lead villain. Maybe as the shadow lurking in the background. Or spending most of his time on command ships... geez, who knows? I guess anything's possible at this point. I'd be thrilled with Vader as lead bad guy but I can't see it materializing.
Hope the style isn't any more kid friendly/cartoonish either. A seamless transition between it and TCW would be important.