I see a few limitations with the way project templates are implemented in v12. First it seems that tasks cannot be grouped. Second it seems that the process of adding a template to a project is only slightly different that duplicating an existing project and therefor not as useful as it could be.
An example for a home remodel.
Project: House 1
-Parent Task: Living Room
–Gut
–Wire
–Sheetrock
–Paint
–Furnish
-Parent Task: Kitchen
–Gut
–Wire
–Sheetrock
–Paint
–Furnish
Perhaps I am viewing it wrong but for this example it doesn’t seem that the project template system is usable. If I could create a template called Room Remodel and include the tasks Gut, Wire, Sheetrock, Paint and Furnish then I could create a Project for a home with 10 rooms and simply add my Room Remodel template to the project 10 times.