Incorrect, you pick it because you’re already right next to it once you’ve got N’zoth. Despite being a terrible capstone, you still pick it because a terrible 3rd capstone is better than any other point left in the tree and unless you’re archon with the apparition talents yogg isn’t very good.
Like yes, Ysharrj sucks compared to the other capstones full potential, and yes the tree is very incoherent and full of extremely weak nodes, but you are still going to use Ysharrj because there’s nothing else left to take.
Scrash is optimal for single target anyway due to tree pathing. Nothing to do with wanting to get DE or not.
VF only increases damage by 25% and only for Archon. Voidweaver will play DA, as it has for all of TWW.
There is no such thing as a rot build for shadow. Our dots are extremely weak and have been all expansion.