Rogue One’s Vader is the kind of Vader I expect in the timeline closer to RotS. It’s too jarring to see nimble Vader so close to ANH. But I mean, I wouldn’t mind a Vader film around that timeline, hunting Jedi.
Using one handed blade work isn’t being nimble; jumping all over the place and running swiftly is being nimble as far as the dictionary is concerned.
You’re right.
Fluid would be the better word.