See, what the WoB says is that if Sazed's power wasn't Harmony it could be considered Discord. To the best of my knowledge op's theory holds true, and you the evidence you've supplied can even support OP's theory. Sanderson said that the name 'Discord' is relevant, but he didn't say how it would be. Just because Harmony is resisting Trell does not mean that it couldn't be a Dr Jekyll and Mr Hyde situation on a cosmic scale.