Might actually be cool if you made "Give in to your Anger" a Force Power that he could activate himself (Force 2, An enemy character with a Force rating that makes an attack against this character to reroll their attack. If the result of reroll is a failed attack, the enemy character joins your squad for the remainder of the skirmish.) That way it would be something he could activate himself, but would cost him 20 HP to do it to. Oh, and I don't think you need both Betrayal and Give in to your Anger.
Another option for Rapid Corruption would be to make it proportional to the number of Force Points spent: 10 damage per Force Point. So, Force Lightning 4 would cost him 40 hit points to use. Could be interesting. That would actually be a really cool ability for a lot of Sith to have. A drawback to allow them to be uber powerful in other ways. Signifies the damage they do to their own bodies by following the Sith ways.
Eternal Hatred + MOTF 2 could be brutal. Would be VERY tough to kill him for good, though I think he'd kill himself pretty quickly from using his Force Powers.
I REALLY like this piece overall. Very good flavor to match the abilities.
As for "unplayable cost range"...well, that all depends on how you cost him.
Just off hand I'd say to put him in the 80ish range to start with. Compared to Sion, he's much more powerful, but does have some draw backs.