To be fair, I think Rian at the very least suspected something like this could happen and wrapped the trilogy in his own movie. There are really so few loose ends that TROS could be a mini-series of epilogues or something.
I doubt that was his intention. If it was though, and he purposely engineered TLJ so that no one would be able to continue the story in a convincing manner, that would be a real asshole move.
As it stands, TLJ really put J.J. in a difficult position and it shouldn’t be a surprise that TROS feels rushed and overstuffed.