I remember @trix180 saying that due to the power of shortcuts, it is unlikely that Bear will include a templater for creating new notes. On the one hand the argument is very understandable, but on the other hand it must be said that shortcuts are not a trivial matter for everyone.
With this in mind I would welcome an integrated tool that is easy to use for everyone. The reference to shortcuts does not convince me because, as I said, they are not that easy to use and an easy-to-use implementation of a basic and fundamental feature seems obvious.
By simple, I mean simple: just a few functions/variables for dates and maybe some for prompts. Nothing fancy.
As far as the UI is concerned, everything could be hidden behind the new-notes button (that one in toolbar of second pane). By this I mean that clicking on the button creates a note, but holding down the click opens the corresponding dialogues for the template UI after a certain delay. This is a familiar element in ux and is actually quite intuitive to use.
In summary: easy to use and without burdening the UI.