HTML Templates should be saveable with a set of parameter NameValue pairs that simply populate the editor interface's parameters screen by default when you load the template for editing.
Presently, if you write a template that requires NameValue pairs, you can include a comment in your template that documents the required parameters and includes some test values, but it can be very tedious to switch back and forth between the template code and parameters screen to input these if you are just trying to quickly load the template and test it.
This could probably safely be done with an additional column on T_TEMPLATE storing serialized JSON instead of going to the trouble of adding an additional table, but who knows?