Welcome back LSM, how's life treating you? 
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Revan is my favorite character ever. And I felt disappointed about how they made him in TOR. (Well whole of TOR is disappointing).
As far as whole Gray Jedi thing I think that is a flaw in George Lucas whole idea of Jedi and Sith (Good vs Evil). I mean nothing in this world is that black and white.
And yes the lack of middle ground in KOTOR I and II did irritate me somewhat. You couldn't choose to be Gray Jedi, you just had to make both Lightside and Darkside decisions. Actually this is a problem in almost all RPG's. Good and Bad is pretty obvious, and it's always obvious which decisions you must make to make the best ending or the worst etc. The only game that overcame this is The Witcher, where the whole world is gray and there are no good or bad choices.
For Example: (Minor Spoiler for Witcher 3) You come across a man whose child is dying because someone has cursed it. You agree to help the man and you find the perpetrator which turns out to be the man's ex wife who he abandoned to be with another women and sired a child with her. The ex wife in her thirst for vengeance cursed the man son. You ask her to remove the curse and she agrees but only if the man renounces his child and wife and comes back to her. The man obviously refuses this and you have to decide to either let the child die, or direct the curse back at the ex wife.
End of minor spoiler.
So I started thinking about the Dark side of Force as a form of narcotic, in the sense of the more you use it the harder it gets to resist it (and there's the degradation of physical body etc). I don't know if many people would agree with this but that's my favorite theory.