THM said:
Plus, they could've taken the time to explain her expertise with ships (especially re: the Falcon) just a little more, and with two basic points - 1) 'I've been crawling all over ships and vehicles since I was a kid', and 2) 'Who's been looking after/around the Falcon for the last X years, you or me? (silence) Right; gimme that spanner'
What? Your number 1 is in the movie. Literally the first sequence when Rey appears and we are introduced to the character, we see her crawling all over ships and vehicles as a scavenger. That's her job and has been for many years, as we see her familiar with it, her having a routine and equipment necessary to work this job and her being familiarized with the whole ordeal (where to sell, cleaning the equipment because she knows it might fetch a higher price, clearly looking for a specific piece for which she knows is useful and will sell).
It's also strongly implied that she is familiar with the Falcon by her commenting that it's "garbage" (how would she know it's garbage if she never explored or at least listened to people talking about the ship?) and by her knowing which unnecessary parts Unkar Plutt had installed in it. Aside from this being heavily implied in the movie itself and I had no troubles catching it, it is further confirmed in the novelization of the movie where it states that she has been inside the Falcon, mostly at night, to look around. Now, I don't think a movie should need extra information coming from other media, but as I said, this was pretty apparent to me from the context of the stuff presented in the movie itself. When I read the novelization, I wasn't particularly surprised, nor did I see this as new information.
(i.e., how/why she's so good with the Force so quickly, not to mention her 'skill' with a sword)
She's not that good with the Force. She mildly resisted during literal torture (which makes sense as her Force power is innate and clearly would activate in times of great stress and pain), managed a mind-trick after three tries on an already mind-compromised individual (a Stormtrooper was the easiest possible target; it has been previously established in the movie that they are trained through brainwashing, indoctrination and conditioning. Not exactly the most strong-willed subject. And it still took her three tries). She managed to summon a lightsaber that was previously established as "calling out for her." These are traits of a protagonist and definitely not traits of someone who's incredibly good with the Force. It's not different from when Luke had the Force for half an hour and then used it to destroy a Death Star without targeting while flying a ship he has never flown before. He did it because he's the protagonist with innate Force power and flying skills; both come from his heritage. Both Luke and Rey are good with the Force for the same reasons. It's almost as if Rey is supposed to mirror Luke directly.
Her skill with the sword is terrible. She had a mild skill with a martial weapon because she was trained with the staff, but that's about it. She held the saber wrong, flailed aimlessly, did literally nothing useful in the first part of the duel and was constantly pushed back. She prevailed only because Kylo reminded her of the Force and she let it guide her (khmLukekhm). And even then, she continued to flail, only with more ferocity and determination. Then she downed (not even fainted) a physically and emotionally exhausted opponent who was bleeding out from a wound made by a weapon that was previously established to OHKO anyone hit by it.
These things have been explained in the movie. I don't find it necessary to hammer them down for the viewer by having them be reiterated in episodes VIII and IX through boring exposition dialogues where two people stand in a room and have a meaningless conversation for half an hour. TFA is not perfect, but it did visual storytelling very well for all characters.