Everything is an object is a nice metaphor but to threat title as an object is a hyperbolization for my taste. Everything inside the canvas is a block for now, even a relation or link to another object.
As far as I understand the original request is to add possibility to mention in the title of page. Am I right?
Another way to see this is that the Title is just a block like any other, parent to all blocks within it.
Have you guys checked out RemNote? It does this very well. The result is a structure that on the surface functions like a traditional page-based system for the casual user, but with enormous potential for granularity and more advanced applications for the more adventurous users.
I appreciate that AT has its own thing going on, of course. Just food for thought!