I said:

>My impression of the template system is that it is about designing
>relatively fixed user macros on a flexible base.  So most of the keys
>are set inside the package, and are not exposed to the user. 

Perhaps better to say that template provides good ways to create sets of
keys which go together (which would be "styles" in pgfkeys or are currently
implemented using the .keys:n property in l3keys).  However, I think the
point that the user does not see the keys themselves stands.

Joseph