My prediction of how the audience might view this in hindsight is that TFA and TLJ will feel like an overextended prologue while TROS will be this mega movie, the one you skip to (RotS anyone?), backed into a corner and ultimately too bloated to gracefully end the ride smoothly, if even intact.
I think this is a pretty apt description of the problem with this new trilogy. I quite like TLJ, but what it didn’t do well was provide concrete motivation for our characters going forward. There are almost no loose ends to tie up and as a viewer, there aren’t very many questions that I need answered.
So now Ep. IX has the unenviable task of starting from scratch story-wise. Introducing a brand new conflict and new character motivations and then resolving them while also wrapping up the trilogy as a whole, resolving the First Order vs. Rebellion conflict. There’s so much to do and so many ways it could go wrong. I would almost prefer it if they left the main First Order vs. Rebellion conflict open-ended and just focused on developing a satisfying story and ending for the characters, but we all know that won’t happen.