Quoted from Daditude:
I would argue that the end of Rogue One is perhaps the greatest moment of the series.
We know what came of the death star plans and how many people lost their lives to acquire them, but it never truly became REAL before that scene.
Darth Vader has truly mastered the dark side and unsheaths all of his powers on the rebels in order to get the plans back. He literally kills dozens of people like it is nothing. They are powerless against him. The chosen one that is supposed to restore balance to the galaxy has not only turned to pure evil...but he is INVINCIBLE. The rebels are running from him in absolute terror. The final rebel holds no illusions that he will ever see the light of day again as he desperately passes the plans through a partially open door, only to have them taken at the last possible second prior to his massacre.
They barely escape, by the smallest of margins, and they are still on the run with the most powerful being in the universe right on their tail.
That scene isn't about jar-jar binks, cute ewoks, or pithy Han Solo one-liners. It is about what they are truly facing; a totalitarian regime hell-bent on the extermination of anyone who opposes them. This is their revolutionary war and their World Wars all wrapped up into one. It isn't pretty or sugar coated. It is a WAR.
For total Vader Badassery, I'd say his conflicts as Anakin, dealing with the weight of his mother being tortured, then slaying those skanky skunky Tuskens and fams, was more drama inducing.
I rewatched the Rogue One end scene after you posted this, and unofficially I'd say scene 38, the redo, is far more aggressive and nasty than Rogue One.
But the prior scene I mentioned, and him telling Padme there was a rampage, lying to her, to get her on his side after he murdered children and anyone that stood in his way, was far more psychotic and ruthless as "Vader" than a chip chop scene leading from Rogue One to a New Hope.
His scene with Padme later, telling her of his betrayal to his entire life, has more weight for me also.
The moments where Anakin has to face his decision making, is far more weighty and consequence filled than a quick hack and slash of some goofy helmet wearing turd rebel turd burglars. For me, it's his transional scenes, from innocent Ani, to wicked Darth, which seem the most drama filled.
His humanity, and therein his loss of it, is more compelling than random murder.