Carthage said:

Vader as a darksider would utilize his rage to sustain him and make him more powerful. That's kind of common for a darksider in the EU and has been for a long time, he did the same thing to sustain himself when he was trapped underneath a building for days and he did it int he RODV novel to make him more powerful in duels

I think there's a difference between embracing rage short-term in the heat of battle to gain an edge over an opponent and embracing rage long-term in some effort to achieve dark side Nirvana; IMO, while Vader is willing to do the former, he is rarely ever willing to do the latter.

In any case, my take on the SW Universe, it's characters, and its metaphysics doesn't mesh all that well with most of the EU's, so the point is moot.