It's almost unfair to have the devourer of worlds in there, you know that right?
We can't really compare what Revan does to those in the movies.
We are able to make some extrapolations, however.
Palpatine: He uses Force Lightning, this speaks to a level of incompetence. After all, most villains have Force Storm when they can grab it. (I know I grab it, even when I'm playing LS) FSrm is a very handy power, if you can wound the others around you enough, and then use it, the enemies are dead.
Compare that to the Emperor... if anything he was using Force Shock, since he was using it only on one person. He was causing Luke pain... he almost killed him with it, so it could be said that Lukes VP's were far too low. (Low Con anybody?)
Luke: He only took several minutes of Force Shock before he was dying. Compare that with any Dark Jedi. They usually resist it, or shrug it off for half damage. Luke's also sub-par with the Saber. (Look at how he wields it! And how he attempted to kill Darth Vader!)
I haven't read any of the Comic Books, so don't think I'm ignoring them on purpose if he did something amazing in them... I just don't know.
Vader: Maybe he was powerful, we'll never really know, will we?
That's all I have to say. It's just an unfair comparison.