RE: Reys fast progression, the ‘Mary Sue’ complaint.
I thought this was explained and dealt with very elegantly in the sequence within Snoke’s chamber. Snoke’s “Darkness rises… and light to meet it” speech clarifies that as Kylo’s dark side power has grown, the Force has found natural balance by also growing the light side. Snoke had mistakenly assumed this growing power was manifested within Skywalker, but in this speech he makes it clear that it was Rey that was the recipient.
I guess the Force forgot to grow the light side when Darth Sidious and his apprentices wiped out the Jedi order and brought tiranny to the galaxy. Every Jedi including Anakin, created by the Force, and Luke have had to work hard at getting control over their Force powers, but Rey just magically gets them, because Kylo Ren stepped on the scene, a poor man’s Darth Vader, and an even poorer Emperor/Supreme Leader. It’s a pretty weak defense in my view.
But there was still Obi-Wan, Yoda and a maturing Luke. This time there was just Rey. Luke had closed himself off from the force and that just left leia. But she also what she said she knew about the force before meeting Luke; lifting stones and controlling peoples minds. Something she heard about and something she tried out ( after somehow being able to block kylo during the interrogation and then failed the first couple of attempts) and was shocked she was able to do it.
Obi-Wan was dead by the end of ANH and Yoda was in a pretty similar position as Luke, having to hide on a backwater planet, and presumably also had to close himself off from the Force to avoid detection by The Emperor and Vader.
Luke couldn’t control his powers even after being trained by Yoda:
Luke Skywalker: But I can help them! I feel the Force!
Obi-Wan Kenobi: But you cannot control it!
To quote Han in TFA: that’s not how the Force works. It’s sloppy storytelling. Even if RJ was following your line of thinking, he should have including some peace of dialogue, where Luke provides an explanation for Rey’s rapidly growing abilities. As it is now we’re faced with a much more obvious inconsistency than the often criticized inconsistencies Lucas introduced with the PT, and a seemingly overpowered and perfect heroine, who pulls deus ex machinas out of her hat like a great magician.