Momemn does seem out of place, particularly with Kellhus showing back up to put a bow on it, so to speak. There's still some interesting stuff there. Notably, we have yet to get an explanation for Fanayal saying that Meppa "does not know who he is", which is an interestingly similar sentiment to the No-God's "what do you see". Also, whatever Ciphrang!Malowebi is doing and Kelmomas's relation to the gods.
My WAG is that it serves a similar function to the skin spies in PON. The primary antagonists in that trilogy were the Fanim, the Cisharum, or Moe depending on who you asked. But the skin spies were there as a pointer to the greater threat on the horizon (the Consult and the Second Apocalypse). Similarly, Psatma and the White-Luck Warrior are the beginnings of the conflict between Kellhus and the gods, presumably to be dealt with in the final trilogy (either exclusively or in tandem with Second Apocalypse).
Personally, my biggest complaint (mitigated by Tekne-Nuke) is that the Consult seems to be following a pretty simplistic and, to be frank, boring strategy. There's only so much "they killed a lot of Sranc, but there were even more Sranc, so the Sranc killed some of them, then they went back to marching" that a man can take. I personally don't think questions about how did Kellhus do/know/find X are as problematic. He's had twenty years with the Metagnosis, and I expect we'll get a lot of answers about what he's been up to in TUC.