That's me, causing trouble.
No trouble at all. Suggestions and discussions are the reasons why I wanted to share those proposals with the community ;)
I like the Warp Affinity. Not extra powerful for casting, but some preventive measures are nice. Makes sense.
Ruinous Rivalry still feels a little clunky. This means that the Chose Squads will have 3 powers (level 1, generates 1 power and gains Psychic or Chaos focus, and then gains an extra power), while Chaos Sorcerers will end up with Level + 2 powers (Chaos Focus + Rivalry).
Is that correct?
Yes, giving marked Sorcerers or Chosen one additional power from their allowed lists (fluffy speaking, each God wanting to show off their Sorcerers are the most powerful ones).
If so, I'd suggest an simpler wording: All characters and units from this formation generate an additional power chosen from among their allowed disciplines.
Deal ! It's actually clearer. In order no to bring up questions about the usual way of generating powers and the necessity to generate half of them on the Chaos God list (for marked Sorcerers), I would just add something like "After the normal generation of their powers, ...".