But a lot of that is being silly-picky with Luke (30 minutes on Dagobah - are you serious?) while allowing books and your own conjecture to back up Rey.
It's clear that Luke is a great pilot, both in ANH and in the filmed/cut ANH scenes. Biggs tells Luke: "You may be the hottest bushpilot this side of Mos Eisley..." Ben says to Luke re: his father: "He was the best star-pilot in the galaxy, and a cunning warrior. I understand you've become quite a good pilot yourself." In the conversation with Han, Han mocks Luke saying "Who's going to pilot it kid, you?" to which Luke responds "You bet I could. I'm not such a bad pilot myself!"
So... it's 100% clear that Luke's a talented pilot.
Re: time and abilities between ESB and ROTJ. When we meet Luke on Tatooine in ROTJ, he's dressed in black and carries himself WAY differently than he does at any time in ESB. He's confident, cocky even, mocking Jabba, much more a badass than we've ever seen before. He has a new lightsaber he built himself (confirmed onscreen by vader later.) He pretty much single handedly takes out dozens of Jabba's henchmen and destroys everything. This isn't at all something Luke could have done in ESB.
The problem with Rey is that it's 100% clear in the way it's shot that only about a week or so passes between Rey playing with a helmet on Jakku and her mincing up those Snoke guards. There's no wiggle room to explain it. This is precisely where this "Mary Sue" thing comes from.
How Rey can not only fly the Falcon, but out-fly TIE fighters in it, going through tunnels etc - as a scavenger who doesn't have food - is never even remotely explained in the movie. You can understand her self-defense skills with a pole, but a lightsaber? It'd be like handing a street-smart slum dweller a fencing sword. However any of this is explained in the books, it doesn't appear onscreen - which is the only place that matters to most.
Doesn't she even tell Finn in the movie that she does not know how she was able to fly like that???