Oh, I thought Darksun simply meant the fact that the war in the north will be over, bringing stagnation to the northern regions again, even if fighting is going on in the south. Or maybe the fact that by having Summerdale join Astrum, neither Morek/Libero could actually win the war, nor could Summerdale. Your interpretation could be right, too, of course, only Darksun himself could tell for sure. Though since he's part of Libero Empire, not of Summerdale, I'm not sure how much he knows about internal Summerdale stuff.