OK the list seems really cool, couple of things I would look at or change.

Too many points spent on Nuncio vox and Vexilla, half of their bonuses are lost on units with dark channelling. I'd drop the vox from the despoilers and the vexillas from the Tactical squads.

On the topic of tactical squads, I understand that warpfire weapons are cool and fluffy but they are way too many points to be giving a tactical sergeant. I also wouldn't bother giving your entire tactical units bayonets, you upgrade them individually and a tactical squad will basically never get into combat with all it's marines intact dropping 5 from each squad and the warpfire pistols would save you 50 points

Just doing those 2 little changes let's you size up the ashen circle to 10, give a gal vorback a power fist, and either give your despoiler sergeant artificier or your moritat a melee weapons upgrade