I always thought the movie was going to end with Rey and Kylo both alive but running their own schools separately, giving Disney the “reboot” template they wanted. As in the series could pick up in 100 years or so with the simple good vs bad dynamic already set up for the next generation of viewers to start over with.
Yeah I think a good thematic “beat” for the ST to end on would’ve been to have the Jedi evolving into multiple factions that all interpret the idea of “embracing the light” in their own unique way. You could’ve had Finn, Rey, and maybe even Kylo each starting their own independent Jedi orders, and then make a new series set thousands of years later with a bunch of different Jedi factions thriving, but not getting along with one another, until a new “team” forms that consists of one person from each faction, to symbolize things “coming back together.” That would’ve been cool, in my opinion.