RJ is good with themes and character archs, basically the deep stuff.
JJ is good with action setpieces and humour, basically the fun stuff.
I think a mix of both is what this film needed.
But that doesn’t require writing (and that’s also ignoring how messily constructed the Battle of Exegol is). When he’s writing he cuts the story and character to make room for set pieces.
An easy example is Rey cutting down Kylo’s TIE on Pasaana. This TIE is new to this film, and in the opening sequence is established to have the McGuffin of the film (one of the Wayfinders). When Rey cuts the TIE down, she’s destroying the ship with what she’s searching for (even if she doesn’t know it, the audience does). There’s no shot of Kylo grabbing the Wayfinder and no shot of him leaving Pasaana on either the shuttle that does have Chewie, or on the Knights’ of Ren ship. Later scenes establish he wasn’t travelling on the shuttle with Chewie and he’s informed of the Knights tracking the heroes to Kijimi, so he didn’t leave the planet with them, we just see him on the Star Destroyer again. Then, on Kef Bir, we see Rey steak this unique new TIE with the Wayfinder after their duel and she takes it to Ahch-To, where she destroys it for a second time. It’s a major plot hole because of the Wayfinder and the fact that this design of TIE is unique to Kylo.
I’m my edit I felt it necessary to cut that fun action scene because it so contradicts the rest of the plot and story.