Well, in Prince of Nothing we are subject to Kellhus' manipulation, we are a direct party to it and even with it being from his own POV sometimes we still fall for it. We see Kellhus as something of a sympathetic figure, a man against the world, an actual savior since he did save the Holy War. In Aspect Emperor, he is aloof and so we see his manipulation much more indirectly which makes it both less overt and seemingly less sinister. Of course, though, without knowing where he is going with all of it means we really don't know if it's less or more.
If Kellhus really did go mad on the Circumfix, wouldn't take make him less apt to have human emotion? Less likely to be an actual savior? I'm not buying any madness really. I think it's all cold and calculated on Kellhus' part. He does show vestigial emotions from time to time, even Moe remarks that this is the case for Dunyain, it's not something out of the ordinary.
Unfortunately, none of this brings me closer to what Kellhus' actual goal is. I think too much in-the-box. No doubt the answer is off-the-wall, but that's not how my brain works.