The SW brand sells itself without needing Lucas' name attached.
Older fans put off by the prequels and special editions will be more enthusiastic due to Lucas not writing/directing.
The visuals and such will be the attraction for younger fans.
Other casual fans and filmgoers probably don't care about whether Lucas is involved or not.
This movie will make a hell of a lot of money because everyone wants to see what happens when Lucas isn't involved.