'What's the problem?
With good reason , high usage or "sensitive" templates are protected from edits by users without certain rights.
However, for some edits, such as repairs to formatting, that can be undertaken by a competent user (that doesn't necessarily need or use full rights), this means that said user (without rights) typically has to create a sandbox, or synchronize an existing sandbox first, and then make thier 'repairs'
For techncially-adept users this process whilst not necessarily confusing is an additional step, which I think could be partially automated.
What's the approach you would like to see implemented?
When a user views a 'protected' template, the Edit button text is changed to an 'Edit sandbox' version.
When the amended edit tab is invoked, clicked:-
If an existing sandbox is present, then it is displayed, along with an appropriate diff between it and the current 'live' version of the template. The text of the edit box will be the contents of the sandbox.
If there is no existing sandbox, then it is created by mirroring the text of the 'live' version into the 'sandbox' before presenting the diif to the live versaion and text edit box with the contents of the sandbox as previously.
In both instances an edit notice will be displayed which indicates that the 'live' template is protected, and thusly edits made are to the sandbox version. To which in the former instance mentioned above, the user has been redirected, or in the latter instance mentioned that a sandbox has been automatically generated for the user to make their edits.
When saving the text from the text-edit-box , the changes made will be saved to the 'sandbox' version.
If needed during the process of saving the 'sandbox' an appropriate notification or edit protected request could also be generated (Although I would suggest this is a check box option which has to be explictly selected) as there may be minor edits to a sandbox, that a user would consider as intermediate steps, that wouldn't warrant a full protected edit request.)