That's just you trying to justify getting instant free mounts and stuff. It's not gonna happen.
If I was working for blizzard I would suggest them to give you a renown level based on your reputation with that covenant. Because yes, we've been doing world quests for them all, so let's say you are exalted with 2 of them, then ok you get all of the rewards, otherwise you get a percentage of renown based on your reputation level.