So in general terms, my opinion.
I don't agree with the general fan sentiment of the season being "oohh soo good! 10/10!". It has its fair share of flaws. In fact, my biggest problem isn't with the end itself, which was fine in the typical David Lynch way, but the slow pace in almost half the episodes, because all the secondary character and secondary plot threads that existed, and that in the end were kind of worthless.
Comparing the season to the original series (first season), in Twin Peaks the story extended to a big cast of characters in a natural way, as the series starts looking into the lives of families that interacted with Laura, and Cooper were around in the town trying to solve the crime. So it transitions to be about the lives of the people of the town in general more or less elegantly.
But in this season, I feel as if the main plot is much more laser-focused, in Cooper's return, Mr. C and the doppelgangers (and Gordon and Hawk related investigations). Therefore switching back to new secondary characters that were hundreds of miles away of the real protagonists, and that barely intersect in the main plot in the most roundabout ways (if any) is silly. And sorry to say, some of the old returning character and scenes are just pure fanwank/nostalgia fodder. I don't really care for what happens to this secondary character for 25 years ago.
And that's not taking in account how long run some scenes... (typical Lynch, I know) for what I think is little payoff.
Maybe increasing the run of the season from 9 to 18 episodes was a curse, not a gift.
On the other hand, when the season had a 'high point', it was really high. Some really good scenes contained in this season.