Make Future WPF IoC Friendly

Something that i really miss on WPF is the ability to avoid using service locators and control how nested controls and pages are created, i'd really like to have some object injected in the UserControl constructors, and a way to tell WPF how to construct them (and maybe provide some mocks for the IDE), instead of the empty constructor.
Maybe since a lot is being rewritten to be core it is a good time to support IoC.
I'm aware that we can achieve something similar with MVVM but... it's not the same...