Yeah, plenty of Gods should be on Kellhus' side. War, pestilence, disease, famine, and the trickster. Though, that's only if the outcome is what they are after, and those aren't just arbitrary things assigned the ciphrang/gods. If the important piece is worshipers, then they would all be against him since he's presumably taking them all away.
I'm thinking that the Demon Gods each have a particular brand of emotions they like to feed on. Everyone really wins except Yatwer perhaps, who can maybe see the end of birth if Kellhus has his way? I'm not sure. I can't remember why exactly she and her cult is after him, other than supplanting the usual religious tradition.
Maybe it's like modern capitalism, Kellhus has a legal obligation to maximize shareholder value (or face legal action) even though milking the franchises with annual increases will destroy its longevity and/or sustainability. Yatwe is the zombie board member shouting LONG TERM GAINS.