That explanation doesn't sit well with me. He was given a bunch of
plot hooks that he could do anything he likes with, and he
chose "none of it matters". He had carte blank to fill in those points however he wanted, he
chose not to, it was not a matter of him being constrained. And it's not like lost. "Who are Rey's parents?" is a pretty general mystery, and by adding the
unknown to a character's background, you make
interesting possibilities to be explored.he could easily have let the whole "who are Rey's parents" thing slide onto the next director, if he didn't want to touch that. But Johnson
chose to address it, and shut down any possible backstory expansion for Rey, basically. So, he didn't
want to do anything with it, but rather than ignore it, he's made sure
nobody can do anything with it now. Johnson actively decided "Rey has no backstory" more or less: she just comes out of nothing, super-ninja-jedi-pilot-engineer-language girl who pulled herself up by her bootstraps, including making her own boots for the purpose. Basically, the mystery about her parents was the only really interesting thing about Rey, but Johnson didn't want it, so he broke it and threw it away, so nobody gets to play with it.
He's not making the
next movie btw, he's making his own trilogy. Which i probably won't be going to the cinema to see. I'll see episode 9 in the cinema just because, but not any of the spin-offs. e.g. I'm not planning on seeing Solo in the cinema either and I didn't go see Rogue One either. If they make "Episode 10" and further, I'll sit those out. I did similar with the Prequels: only saw Phantom Menace in the cinema, decided "nah", then decided to skip the others.
Here's a good laugh for you
https://movieweb.com/star-wars-9-crawl-fake-fixes-last-jedi-problems/