I am an enthusiastic user of the existing template feature. There are two changes which might further improve it.
At present, a template is always inserted at the bottom of the page. I frequently need to cut and paste to move it the my preferred location. It would be more convenient if templates were inserted at the cursor location.
I use different templates for different days of the week. It is easy to insert them manually but it would be even better if they were inserted automatically. Rather than complicating the "Settings" menu, I suggest that this might be achieved by creating "reserved names" for templates.
For example; A template named "Monday" would automatically be used as the default template for Mondays, whilst "Friday" would be the default for Friday. Other possible reserved names might be "Weekend" and "Workday".
I realise that these are both trivial issues and would not expect you to address them if significant code changes would be required.