Jumping in on the Ren/Finn/Rey fight discussion... The descriptions we got iirc made it sound like Finn kind of got steamrolled, with Rey also getting handily overpowered (with the implication that Ren was apprehensive about finishing her off for whatever reason).
This seems to make sense to me. Kylo has likely been a dark side user for many years, possibly a decade or two even by now. Maybe he has never faced a legit saber opponent, but we have no reason to think Finn (especially if we assume he has no force sensitivity) should be able to stand against an experienced (even if not fully traditionally trained) force user from the Skywalker bloodline.
If Finn holds his own TOO well, I feel like that would diminish Kylo as a villain.
It would make sense that Rey could potentially hold her own more, but having her do "too well" against Kylo could also diminish him as a villain.
I'm a little concerned that they even have Finn using the lightsaber at all (if he's not force sensitive) but until proven otherwise, I'll trust that Abrams and Kasdan knew what they were doing and got the balance right for that scene.