Rose is a better character than Lando was. Barely. But still.
Seriously? Lando was a pretty pivotal character and really set all the events in motion for the 2nd half of the movie. He partnered with Vader to trap Luke and in the process got Han nearly killed and shipped off to Jabba (remember?)
No Lando: no cloud city, no luke/vader duel (no “I am your father”), no carbonite, no Jabba, no reason for rotj basically.
What exactly did Rose do that was so important (besides setting free horse-llama things and preventing Finn from committing an act of selflessness)?
Most of the movie doesn’t exist without Rose.
In that she occupies a lot of screen time, yes. But her presence in the film is inconsequential. She accomplishes nothing. Like I said in a previous post(s), you could cut her character totally out of the film and it would have no impact on the plot, such as it is. The whole casino/code cracker subplots could be eliminated entirely. It wouldn’t have made it a good movie, but it would have at least made it tighter.
I wish they’d filled some of that time with more training scenes with Luke and Rey. I would have loved to see Luke kick Rey’s ass in a lightsaber duel as part of her training. I would have loved to see him in a duel one last time. 😦