You know i completely forgot WOT declared the third exalted march ending in stalemate, but having just reread the section, it does.
Good catch Baconner.
Well there you go.
The Qunari had lost all the territory they had managed to gain, they were stuck in one little craphole of a fort at the ass end of rivain and it was under siege, it sounds like they had no where else to go 
So yeah, if the war had continued...what would have happened?
The Qunari would have been slaughtered in their little fort and done what? Lament that they didn't didn't bring more soldiers?
If they had more resources, i'd think they would have committed them by now.
There you have it: Word of God states the Qunari were all but defeated.