It isn't so much a matter of declaring motivations (which even the prequels do), as establishing motivations. If the motivation is fairly expected and pedestrian, like Rey's desire to help the droid in that early establishing shot, then we don't need a great deal of setup--the simple contrast is enough. (I thought that scene was a fantastic take on the Be Nice To Animals trope, btw; and it did plot work as well!)
But if the character is acting against her own self interest, then more work is required to establish their motivation, else the narrative risks its characters acting stupid on demand (e.g., exhibiting contrived behavior for plot convenience.) One of the points that bugged me was the scene on the forest planet (I don't remember the place's name) when Rey insists that she's going to return to Jaku, despite being aware that she can do a lot better for herself. Who is she waiting for that she's willing to undergo so much hardship to wait for them at Jaku? Why is it so important that she personally be there, rather than just pay someone to deliver a message? Rey is the sympathetic protagonist, the character the audience is meant to follow and learn with, but in this scene her motivations are left to the imagination.
I understand that her reasons are probably being withheld for a reveal in a later installment. But personally I would rather wait and see THAT movie, instead of being strung along with a less-than-perfectly comprehensible protagonist, waiting for the punchline which never comes.
Why is that confusing? She's an abandoned kid. You don't ever stop being an abandoned kid. She has to wait because they're coming back. Sure, that's never going to happen, but just being gone as long as she has will have had her mind becoming more and more convinced that she may have missed them. They may have come back for her, and then she wasn't there. IT takes a lot to force someone out of that mindset. "Doing better for herself" isn't a strong motivator. In fact, for many people, in general, it's not a strong motivator.
The movie also suggests so strongly it might as well be explicit that she is waiting for family. Whether that is literally her parents, or someone with a similar role in her life at a young age doesn't really matter.
"Why does she run away from the lightsaber? Why did the vision scare her? It didn't scare me. Again, I need to know the protaganist's motivation."
It took me a while to know where to begin with this, because it just seems almost explicitly obvious. First of all, she's never experienced anything like that before. Second, the vision demands of her that she fulfill a destiny, one that runs counter to her obsessive need to keep faith that her parents/whatever will come back. The vision also shows her some dark stuff. It's totally nomal, especially in a story, for someone to run from something like that.
And there is literally nothing in the film that suggests that Rey is one of Luke's former students. She certainly isn't well trained with a lightsaber. She not only vaguely uses it like a staff, she also hesitantly mimics Finn's stance when she starts using it.
Maybe rewatch it without that impression, and her motivations will make more sense to you?
Let's see...the need to find Luke:
He's Leia's brother. If there was nothing else, that would be enough.
He is the guy who trained Kylo Ren. If there was nothing else, that would be enough.
He is the most powerful and knowledgeable light side force user anyone knows of. If there was nothing else, that would be enough.
He's the guy who defeated Vader and Palpatine, the guy who destroyed the first Death Star, probably the greatest hero of the Galactic Civil War. See above.
He's the last Jedi. For both sides, that is enough.
the Map: Why on earth would he leave it in one place/piece? That would not help him stay hidden. He left one part with R2, a trustworthy and reliable ally who has delivered such valuable intel a time or two before, and the other piece with an old friend and ally that most people would never even know to look for, hidden on a backwater world.
What about that doesn't make sense?
