Yes, forgive me for making the clearly foolish assumption that what the creators of the game have to say might be relevant to interpreting the game, especially since the game is still incomplete so whatever they say might just indicate what sort of things will be implemented at some future date...Given how much weight you put on Word of God rather then the actual in-game content and what it amounts to, I'd be rather surprised if you did more reading then I to be perfectly honest with you.
There is literally zero need for an actual war effort if their goal is to wipe out Kas? You know what it would take? One of these seven fucks with their occasionally reality defying power to do a fraction of to her...
The Doylist reason they don't do this is that then there wouldn't be a game if the gods could solve all your problems for you with a wave of their divine hands. Garde has been quite clear on this, though there are plans to get into the specifics of why this doesn't happen if you insist on a Watsonian explanation.
And I never said the wraithtouched aren't a problem, but their numbers likely are depleted in regards to non corrupted life, whom they presumably need to prey upon in order to restock their own ranks, otherwise they're producing basically super imps in that they're naturally soulless shits and thus are morally justifiable to murder according to the devs, since Imps are fully sentient and yet no one bats an eye and stomping them.
Their numbers are enough that divinely empowered warriors have been devoting their full attention on them for decades and are losing because again, the non-wraithtouched population isn't growing fast enough to hold new ground even when they manage to briefly take it. What the Champ can potentially do has already helped shift the balance back in favor of Team Good Guys but it doesn't mean these things aren't a serious problem that has been occupying a lot of time and resources for the past few centuries.