Adjusting Leia’s death and disappearance runs into some issues.
So you have:
• Leia sitting down and calling out to Ben.
• Leia’s hand going limp.
• The Resistance surrounding her covered body.
• Poe coming back and speaking to her body.
• Her body disappearing when Ben dies.
I had the idea of placing Leia’s disappearance right after Kylo turns back and throws his saber away, helping to imply that Leia played a part in the vision of Han (though that still could be the case). I wish Leia said more than just “Ben”, as well…
But that runs into issues depending on where Poe’s scene with her is placed, and I can’t recall its placement at the moment.
I also think you have to have Rey stabbing Kylo, because I think that her almost killing Kylo is why she decides to hide out on Ach-To, but maybe her Dark Rey vision or pushing Finn could be implied to be enough.
Regarding the political situation
Now that we know a hidden Imperial Fleet is out in the Unknown Regions, I definitely think it would be better if the First Order was depicted not as mysterious or hidden, but as a unified Imperial Remnant on the fringes of known space.
Maybe the TLJ crawl could start out as: Chaos reigns.
I also think one of Nev’s crawls said something about both factions suffering major setbacks and both are desperate to snuff out the other, which would fit well.