You know, I don’t think Darth Vader really should be depicted as agile in the cybernetic suit. Vader in the OT - particularly during the ESB duel - was more like this methodical, slow-moving, unstoppable force that just keeps slowly advancing forward. I know people won’t like the comparison, but I think Vader was somewhat designed to invoke similar fears that someone might experience watching horror movie icons like Jason Vorhees or Michael Meyers just silently walking forward like an unstoppable hulking mass. Rogue One certainly capitalized on this aspect of Vader’s aesthetic. I mean, Vader basically lives in a dark tower on a Mordor planet - an idea going back to the 1970s, pre-dating Rogue One by decades. He was never meant to be agile like Darth Maul. He’s meant to be a slow, imposing, unstoppable hulk. These physical mechanics are inextricably tied to the design of his suit.
I agree with all of this, I never really said or believed he should be that agile either. I just get annoyed when people act like he’s geriatric and anybody in the PT would whoop his ass (they wouldn’t).