This would take place after the possible Karzahni arc.
Regarding Annona: The idea behind her is as a personification of all of the Three Brother’s worst qualities, as well as an uninhibited creation. She doesn’t have to be connected to the Brothers or Mata Nui, but that’s how I introduced her in the Mata Nui and His Sons pitch. This could reinforce Makuta’s drive to control, to prevent an Annona-type situation.
Regarding Mata Nui’s revival: The way it’s been thought for Mata Nui, He is tied to the existence of the Nuva in some way. If He dies, the Nuva die, and then Artakha dies. The only way to ensure He does not die while he’s in a coma is if he is stabilized and woken up, to prevent being taken unawares.
As for His purpose in the narrative, He’s a major character in G1 (being the central plot point of the entire G1 franchise). I’m not sure how He’d play a major role, but not having Him play a major role seems like a disservice. It’s similar to your argument with Takua’s character being introduced, but on a greater scale.
Regarding Turaga and Toa: Fair enough.
I’m really happy you took the time to read through this pitch and offer feedback. Again, this pitch doesn’t have to be used; it’s simply something you might use for source material.