I am not totally agree with you.
Yes what you say is correct, but lacking.
As any goauld present him/herself as a god/des to the Jaffas figthing for him/her to prevail.
BUT they also recognize the rivals as gods,
and if a Jaffa serving a Goauld express distrust of any other Goauld, even the worst enemy, it is immediately remembered by his lord about that.
This has been show in an episode in which Teal'c remembered when he was serving Apophis,
whom he joined as the enemy of Chronus who killed his father,
he express his motivations to his new lord, who, surprised, in a very direct manner answered him that he was serving his god, and if he decided to kill him, he was right, anyway.
A Jaffa have to believe that goaulds were gods, only to change flag when someone lose, but without negating the divinities of the former or any other goauld.
So it IS a united religious system, the Goauld System, about that matter.
So representing as many religions as Goaulds is actually more incorrect that one.
Also, two notes: this is a mod for a game, there is a religion for any civ (ie Asgard protected worlds - but there were at least both Thor and Freya)
We cannot have a religion for each Goauld/Asgard/Ori because it would became too overcrowded to play and complicated to realize.
Also, game is set to have 7 religions, for a matter of balance.
EDIT: @dataskywalker - is this project still alive? I hope so.
