For now, it is impossible to control the visibility of elements on the Title Block as it is a standard for other families. The only thing we can do is to change the label's text.
It would be very convenient to be able to show/hide elements in Title Blocks as "instances" with yes/no parameters using schedules. It is a very tedious process to open and click every Title Block instance to change these parameters.
Why Sheet Parameter can not be assigned to the Title Block (where it would be more meaningful), as to the Sheet?
I hope that the parameters in Title Block will be somehow associated with Schedules to improve workflow