Hal 9000 said:
‘Heir To The Jedi’ Duology
I digress. As I said, I think a TFA-TLJ duology is greater in total than a TFA-TLJ-TROS trilogy. The only thing that would make that feel weird is the trilogy structure the audience expects. As an absolute minimum, all one would need to do is either do away with the opening crawls (and finding another way to set the story and political landscape up for TFA), or replace their “Episode” labels with something like “DUOLOGY TITLE - Part I - THE FORCE AWAKENS.”

WOW , that is an extreme measure! i loathe TROS (is reductive , uninspiring and dumb) and love TLJ, but i don’t think that TLJ would work as an finale, is too open ended, with questions as:

“What happened to kylo? he just stayed bad and died offscreen?”
"knights of ren that we saw in TFA whats up with them " (they did nothing in tros, but at least they were there) - “how would kylo act as the supreme leader” (we see a little of that tros, not much but a little)
“What did rey do with those books?”
“is hux going to betray kylo at some momment?”
“what is going to happen between kylo and rey, with the new status quo”

If you want you can make massive alterations to TROS (no rey palpatine, no palpatine, no jannah or zori, sith troopers being under kylo’s command), but i don’t think that dropping TROS altogether is viable.

although i would prefer for an improved TROS over that, enjoying a fan edit so different to the actual movie , gives me the sensation of enjoying something that is not real, the sensation of indulging in a headcanon.