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.
That’s not necessarily a good thing…
Well, maybe if you don’t like the movie. But on the question of whether her character is of consequence, then the answer is clearly yes.