I'm not a supporter of TFA or what JJ did. But I accepted it, waiting to see where it was headed. JJ hinted and made us believe that questions would be answered in TLJ. The why and how from what we saw in TFA. Johnson chose how to address or ignore those questions.
JJ literally made Rey as confused to how she could do these things as he did the audience. Rian did not answer that in TLJ, and yes Rey was even stronger in TLJ. Not just lifting rocks (which she never used the force for in TFA), she took on a bunch of highly trained guards, Snokes bodyguards, in the throne scene. Not a tired, injured (the foreshadowing of making chewies bowcaster sooo powerful), angry and then confused Kylo Ren who didn't expect Rey to do what she did. Remember, Rey looked confused when the lightsaber flew past Kylo and into her hands too. JJ had rey use the force more as a defense under duress/natural instinct, than learned abilities. Having a s ingle lightsaber come to your hand under extreme emotional duress is far different than giddy smiling as to lifting tons of rocks at a single time. Luke struggled with and could barely lift some rocks in ESB after weeks (months?) of training with Yoda. Luke failed because he couldn't "believe". Rey succeeded just because she did "believe"? Whatever...
And JJ created the mystery as to why and where Luke disappeared too. It was Rian who decided the reason was he turned his back on his friends and the Jedi, and went to the island to "die". And that Kylo fully turned evil and embraced the dark side cause uncle Luke tried to kill him in his sleep. None of that was in TFA nor even hinted at by JJ. That was all Rian Johnson. Just ass trying to get a cheap laugh at a very emotional scene of Rey handing Luke the lightsaber leaving us all gasping at the end of TFA. Rian's answer was to make it a gag joke and have him toss over his shoulder, not JJ.
And R2 was asleep, yes, I'm fine with that. But again, once Luke was back in the picture, R2 could've done more, as could 3PO. They are his droids, not Rey's or Finn's. They should have been featured more prominently in TLJ, as JJ may have intended with Luke's return. But again, Rian made them useless, not JJ.
I could go on and on....