I think that's what makes the faults of TLJ more annoying, TFA was just such a mediocre film all around that there wasn't really much to pick out as obviously worse, TLJ did have some good ideas in the Kylo story but surrounded them with so much crap before dumping the whole thing anyway and just turning him into a straight badguy.
Imagine TLJ ending with Rey either joining Kylo or perhaps being undesided with the two of them being separated by wider events, doesn't that make the last film about 100 times more interesting?
Luke rejects Vader at the end of ESB of course but that's not the same at all, the "I am your father" reveal and indeed losing to him aren't really geared mostly towards Luke joining him, there geared to destroying Luke's more simplistic heroic fantasy and that damage holds over into ROTJ.
Again I suspect Disney might well be behind that, too concerned with Rey being an "equality princess" rather than actually being an interesting character telling Johnson he couldn't take her in that direction.