I don't think anyone would call RBG a poor documentary - aside from glorifying its protagonist (and hell, she just might deserve it anyways), its exposition is clean and is about an important subject. That said, I will be quite disappointed if it wins best documentary at the Oscars. It has neither the deeper character and surrounding political climate present in Won't You Be My Neighbor, nor the intrigue or human nature considerations in Three Identical Strangers, yet neither was even nominated and RBG now seems like the front runner!
Focusing on this documentary, it is a pleasing narrative but unremarkable. It is clear who RBG is throughout, and we don't really get anything deeper in her character than a quiet, intense person 100% committed to their task as judge, and very committed to ending sex-based discrimination. I would've liked to see more of the opposition she faced and the real intricacies of her fight - it seemed more like she worked really hard and change just happened naturally as she focused on it. I also didn't get a good sense of her personal life or what her job as a judge is like, a missed opportunity. I really don't even know what she believed in aside from women's rights. It's easy to watch and enjoy this appreciation for an enormously impactful and relevant American figure, but it's unfortunate that the picture is so one-dimensional in representing her and just shows her perspective and not much of others. Fine film, but superficial and forgettable.