I think you make a good argument, but as far as the explanation you were requesting... I have a few ideas. Reason number one, she is instantly with no training more powerful than the sith apprentice. Why is this so significant? Let's look back, darth maul kills Qui-Gon Jinn, the entire time he's toying with him as if he's not a challenge, and he's dueling Obi-wan at the same time. Now I want to bring up another point before I continue, Anakin was the chosen one, supposedly the most potentially powerful being to have ever been. Now this whole storyline was taken as not a rare instance, but what star wars is, and thats because Disney Doesn't know Star Wars, what they've made is taken from the face value of the movies and ignoring major details, Rey embodies that whole point. So count Dooku bests young Anakin, he then bests Anakin and more experienced Obi-Wan simultaneously after Obi-Wan had already beaten Maul. Dooku then nearly beats Anakin at twice that power level, while wielding two lightsabers (Yes George Lucas stated that he was actually twice as powerful) But keep in mind, this was the only instance of this ever happening. The only reason Anakin was around was because the Force required correction, and so it created him, with only one parent. Now we go back to Rey, she beats the sith who had nearly whooped Luke, who was stated to have achieved power close to Anakin. She does this all with no training whatsoever. Next issue, the way that she fights. The actor herself spent more time choreographing fights than the prequel characters. You can see this in the actual movie, her fighting isn't clumsy, its precise and unrealistic because for one, lightsabers have no counterweight on the blade, it is just a lightweight hilt, and an energy blade. I've heard the argument made that she has fighting skill from her staff. Sure, she may have had to fend off some muggers or such at some point, so she might have used her staff defensively at some points in time, but this was certainly not the daily occurrence through the years that would have equated to years of Jedi Training. Assuming she's somehow mastered the weapon, again, the weight in itself will cause her to overestimate attacks, swinging too hard and too far, leaving her open to be attacked by Kylo, but this is not what we see. Another thing, the staff is obviously a longer weapon, you see her have her hands spaced out widely across the shaft when using it, that does not at all translate into the tight closed grip of a 10 inch handle. The force can give people short term premonitions of an opponents attacks, which accounts for part of her well... the fact that she didnt die, but even so it doesnt give you any practical defensive or offensive skills with whatever weapon you would be using. Next point, in the original trilogy, nobody knows about the Jedi, they're myth, anyone who claims to be one is either crazy or a "space wizard", back to the sequel trilogy and you see the same is the case, but maybe even worse so, because there was no revival period, where there were a lot of Jedi everywhere, at least not in Disneys new canon. So how does Rey seem so knowledgeable in the lightsaber combat, she uses stances, attacks and poses consistent with Ataru and Shi-Cho. Forms of combat that were made for use in lightsabers specifically, well... Shi-Cho also works with swords but you get the point. Im going to ignore her immediate knowledge of the force pull ability seeing as it is situationally similar to Luke learning it, but I still think its unlikely how early she learned it. Luke thought things like that would be impossible for the longest time. If you rewatch that first duel, her sparring skills are just too great, and the specific Jedi techniques couldnt have just been learned in the background, there is no source for her to learn those from. Next, she performs a roll, with the lightsaber ignited and knows the exact placement to not injure herself. Not impossible, but it seems unlikely that she would be that confident and flawless in execution. The other thing is she doesnt defend herself desperately like any other untrained character would, without major hatred or darkside related motivation, she offensively charges Kylo Ren, and there are at least three instances where she attempts to impale him, rather than the more traditional slicing and parrying movements. Kylo Ren has a cracked crystal, making his lightsaber blade unstable, it sparks and stray energy arcs outwars, you can see this when he goes for an upward strike, being blocked by Rey. This in itself seems odd when she only now struggles after starting that whole fight so confidently. You can see physical strain in her muscles, and she arcs her head back away from the flying sparks, next scene, she's up with no strain, in the same position except her head is up right next to the blades, as if she's suddenly inexplicably gained the upper hand, ready to parry. Which of course she does, but again, about the strain, she's seen gasping, struggling under the pressure, then next camera angle there is no struggle, she's breathing fine and she's having a conversation. This is also dumb because there are a good 10 seconds where she has her eyes closed, and Kylo Ren just sits there, he makes no offensive strikes on her at all. He, being an experienced trained Sith Apprentice just sits there in the same position, wasting a long window of an opportunity to finish the fight. This conveniently works out for Rey to win the duel. Next thing, after that brief 5 seconds of apparent struggle to make the fight more "realistic" she immediately whoops Kylo, and hand to hand she physically overpowers him. The likelihood of this is increased by the fact that she jabs his shoulder, leaving the arm less useful, but its the wrong arm, she pushes his sword arm into the ground, the uninjured one. So yes, there are many things I and other people hate about this character, I could go on for much longer but at this point Im not sure if you'll read this far into me trashing Rey. The actor herself says the character has no flaws, every flaw that has been pointed out, she argues is a strength for the character, so of course that makes her less believable, likeable, and underdeveloped. Even then, why does this make her the prime example of what is wrong? I dont think she is, Im sure that it could have been much worse, it just bothers me that Dinsey went and said 96% of what is Star Wars is no longer canon, to make their own 3 movies that have a ridiculous amount of flaws in them, that they disrespected George Lucas's wishes and ignored fan opinions, and they still didnt come out with a good acceptable result, that bothers me. I don't think she's a bad female character, she is a bad character, one of the worst in the franchise, but I, among others place a lot of what is wrong with the sequels on her, because she is the face of that trilogy. And there is nothing wrong with that, people did it with Han, Anakin, younger Anakin, Jar-Jar, even Palpatine. I love Star Wars and it upsets me that they changed so much of it for profit, and still downgraded even lower than my expectations, the nostalgia of those movies is really special to me but no, its not the worst result in a character.