Having an option to turn anything to template, down to a single element, is just what a modern super-powerful theme needs.
Template manager looks great. Perhaps an option to add Categories would help organizing more complex libraries. There is still room to the right in the table.
Also, I would like to have an account on Apex, where my personal library of everything exists. And then I'd like to have a third option in X, "Load from online library". If that library can also hold code snippets and stuff... Oh, ok. I am asking too much. Or not?
Can't wait to fully utilize new X/Pro in the next project!