I dunno I mean. The fact of the matter is, he pretty much came to an inglorious, bitter death.
What exactly is wrong with an inglorious, bitter death? Its an end nonetheless. It is what most major figures get to experience. I think what Revan did in TOR, was meant to alienate both the republic and empire players from him, make him sort of neutral or a mutual enemy. Would you have preferred he die as a hero of republic? That might have annoyed those people who played him as a dark side figure.. And vice versa. This was a sort of neutral ending.
Also, having the same ending for both sides makes it easier to write continuation to the story.
Acta est fabula, plaudite.
(the play is over, applaud)