Johnson laid down plot threads
That he severed moments later. Yes. That was the biggest issue with his flick, in how he sabotaged any new interesting characters and material at the onset, providing with a rather good ending, but leaving with nothing appealing to follow.
Holdo being introduced as a leading heroic character then killed later...
Luke being killed for no reason...
Resistance contact on Canto Bight set up as an aide to the protagonists, but ending up being a useless rich brat..
That Del Toro character being introduced as an aide, then is apparently killed (?) after revealing himself to be a full-evil traitor...
Snoke being set up as an immensely powerful bad guy, but later killed without any more explanation of who/what he was...
....actually it's hard to find a plot thread that was NOT severed in the same movie. Besides Broom Kid who surprisingly wasn't killed, lol