e-smith API was made around 1999, updated and maintained since ages…it is something that NS has cleaned, maybe it is time to make something new and better.
Yes IMHO, when a template is no longer present in the rpm or of course if the RPM is no longer installed, the template should not be present anymore.
Obviously, saying that is easy, to make it possible is another game. FYI I do not like the %post way, we should try to do by another way (the esmith API)
Actually to remove a template, the official way is to expand it with a content DELETE=1 inside.