Seriously, I was disappointed in Kylo being dragged into a Vader redemption path. I think it would have been cool if he was the final Arch-villain, perhaps himself killing Palpatine even if that meant the Emperor's spirit passing to him instead. He seemed commited and would be cool with that if it came with a major power upgrade.
Also I'm half serious here, but as Rey reached out to the Jedi of history, I wish that one that was heard back from was Mace Windu. Then contrive something in the story so that Finn gets a purple light saber and channel the rightous fury of Mace Windu's Force Spirit for a motherf***ing rematch.
Yes that's ludicrous, but it would have been amazing.
I should be a director.