I wouldn't consider the Zereths as manifestations of the Progenitors, more like extensions of them@LeConceptuel
Not to be that guy but at least for me part of the reason your points don't always seem to be clear is because you write like you were trying to parody teenagers writing or something like that.
Regarding your actual points: I agree that there's a lack of clarity in how Light and Order specifically are different is a problem. I completely disagree in regards to the avatars, I think that if there is one aspect Blizzard has done right regarding the Pantheons is how above you they feel when compared to mortal characters. They may not feel alien enough, I agree on that, but they do feel transcendent. I also feel that you're overstating a bit on the cosmic war stuff: sure, you have folks like Denathrius or maybe Dimensius who wish to further their Force's reach, but consider how the other Eternal Ones or even some Titans (remember Eonar and Elune being besties?) just seem to want to carry on their duties. I agree on the fact that each Force having its own Zereth is dull, but the new details about the Zereths themselves being the manifestation of the First Ones help mitigate that.