Re: Mary Sue
She could be "one with the force", but the movie director gave no background to her. There is one specific youtube video where the guy discuss this, and I agree with him, they gave no justification for her to be so attuned with the force.
They gave it to kid Anakin, where his mid-chlorians were "off the chart". He could have empowered Rey to his heart's content, but he should have given more of a background story. No such thing happened.
And Princess Lea, all of a sudden, "woke" in the vacuum of her exploded ship and propelled herself back into a vessel. What the flipping $deity. BUUUUUT, she was the daughter of Anakin, just as Luke.
They said Rey was "a great pilot". That could be further explored, like her "dodging" stuff in a manner only Jedi do, just like the pod racing with young Anakin, as the young Rey pulled her shenanigans to get her hands on the Millenium Falcon, for example...
I blame budget.
As it is, she is a god-damn Mary Sue, she can do no wrong, she is flipping perfect, with no story to back her up.