Okay these are a few things that would lead on from what we saw but also give us some entertainment value

fractures in the First Order with the military vs the weird cult leaders
fighters joining the resistance as a result, or from distant systems that heard what happened at Crait
Rey using whatever is in those books
Expansion and conclusion of the balance plot as a result
Poe and Finn becoming competent at their jobs and leading a final assault
Luke Ghost stuff
Kylo mommy issues stuff that is now very tricky to achieve

The problem now is you have this terrible Rose love plot that does nothing, when she should have rescued Finn after his ship got hit by the laser machine to finish the ‘never meet your heroes’ plot thread. A week after seeing it this is the part that feels the worst in both terms of inclusion and execution.

Mystery Box Bonus round:

Rey probably forgiving her parents or something
Snoke ghost or resurrection / Vader mask stuff conclusion