Tobar said:

Well this is set just before the start of Star Wars and we see Vader fresh on Leia's heels chasing after the plans, so I'd say it'd be more appropriate to see him in this context than most others.

I'm sure Disney is dying for a chance to use him in one of these films. I wouldn't be opposed to a cameo, just as I wouldn't be opposed to Leia receiving the plans in the film (though this would be better done offscreen or implied). I'd hope it would be better handled than the ending of Sith, though. ("Look you guys. Full circle! FULL CIRCLE.")