I believe the entire purpose of Driver pursuing Soderbergh (who then got Burns onboard) was primarily to investigate the idea of the character not being “redeemed” - Driver had initially signed on thinking that was the goal with the guy, and that had been reinforced by how The Last Jedi was done.

I don’t think they were trying to cement Kylo’s importance to the overall story, really. In fact, his being forcefully, clumsily shifted to hold almost the whole focus of the ST by the midway point of Rise of Skywalker is a huge reason it folds in on itself, dramatically - the movies start by pairing Rey and Finn as the co-leads, and then Rey takes center stage for the 2nd chapter, and instead of Finn & Rey coming together for the 3rd chapter, they backseated both of them for the sake of making Ben the hero/main character. Say what you will (I do, all the time, LOL) about Trevorrow’s skills as a creative, but at least his first couple whacks at the story recognized where The Last Jedi was pointing towards, and it was NOT a “redemption” for Kylo, and it was 100% at Finn leading some sort of uprising amongst the First Order (which is probably the only way the Resistance overcomes having almost no numbers).

This seemed to have been a story looking to pursue the original idea in a different framework. Kylo/Ben wouldn’t actually be prominent to that degree, he’d be hunted, and the clumsy, facile idea of “redemption” forced on him would be sidestepped for a more interesting examination of the character who actually IS too far gone.