I have a lot of track extras in templates that I would like to hide unless needed
Just asking…
Can’t you just start a project with your large template(s) then, hide the tracks (using the visibility tab) that you want hidden, then resave that as a new template? I would think that the tracks would be saved as hidden in the newly saved template.
Regards. 
Indeed, this is the way to do it, no new feature needed.
Not if you go to show all hidden tracks.
What would you want to do? It’s very configurable with the PLE.
The ability to lock-hide extra output and input channels in the mixer that aren’t being used but potentially may be used but I dont want to see come back into the mixer every time i use ‘show hidden tracks’.
So don’t use the Show All Tracks command.
Create a condition on those tracks or channels that the PLE can filter –like the name– and create a preset that shows all tracks except for those so named. Invoke that preset from a keystroke.
Or, put the preset it in the Visibility folder of the the PLE presets folder, and it will appear in the Track Visibility Agents>Advanced Agents menu and the Edit>Process Project Logical Editor