Was what was left of Thanos' boobytrap from within ISAAC merged with the then-damaged Control Crystal within Vision what caused the world-domination scheme (ISAAC's normal duties/ programming on Titan being changed/ warped into a standard "take over the world" plan based on elements from both Thanos and Ultron?

Read more of my theorising here:) http://fanfix.wordpress.com

That and Immortus probably nudged the whole thing along. Part of destabilizing Wanda's life was removing her husband the Vision and her children. The fear of the Vision taking over the world's computers again was the impetus Cameron Brock and Vigilance used to have Vision dismantled. And the dismantling of the Vision allowed him to use Horton/a space phantom pretending to be Horton to disseminate the bit about Vision's origins.