Rey still beats way more experienced people than her easily. In New Hope Luke is clearly shown out of his element in the dog fight. He needs Biggs, Wedge and Han to save him and while his one shot that he is already good at is guided by the Force, Rey is possessed by contrast. Mary Sue indeed.
The First Order “plan” only worked because of a highly coincidental sell out by DJ. And mini hyperspace jumps are well established as being possible. Even if they wanted to avoid any danger. A bunch of ships could jump away, then jump back in front of them since they know where they will be. This plan was about as smart as Hitler letting the Brits escape Dunkirk.
As you say, Luke is an old man and should not just be learning that failure is a teacher. He figured that out big time in Empire Strikes Back.
i dislike how these movies have undone the progress of the main characters from the OT and put them where they were at the start. Leia running a rebel cel, Han smuggling, and Luke being a whiner. When we saw that Luke was exiled in Force Awakens and a glimmer of why, I don’t recall anyone being offended at the time. I’m sure most of us could imagine reasons why he would do that. I doubt many came up with curling up to die. We were likely expecting a plan like why Obi-wan and Yoda were hiding. Off he top of my head, Luke has a vision of the future of a powerful apprentice seeking him out and is waiting for it to come true.
I applaud the effort to be different, especially after the Force Remakens, but being different is not a guarantee of being good. In this case the blemishes overwhelm the successes. There was much risk taking I enjoyed, but the whole does not hang together, especially with Luke.