The best thing about the Force Awakens? More than a few of my friends who previously had no interest in Star Wars are suddenly very excited about the franchise. They loved the new cast and so do I.
I never think about on-screen chemistry, but these guys had it.
That does seem to be the case with a lot of people that previously had little to no interest in Star Wars. And perhaps there's enough gamers in that crowd that will be willing to check out and support FFG's Star Wars RPG efforts.
As for how a film can be negatively impacted by lack of on-screen chemistry, look no further than the "romance" scenes between Anakin and Padme. By contrast, Ewan McGregor's Obi-Wan had pretty good on-screen chemistry with pretty much anyone he spoke with, but that's probably due to Ewan McGregor being a pretty solid actor in general no matter who's directing him.