The idea of identifying a profile with a template I think arose while the idea of "actively managing" was much less developed. My first project was Magna Carta, where it was a strict rule that the template got displayed only AFTER the most active management process of expanding, editing and correcting the profile had taken place. It was not at all clear to me at the time, from my perspective, what residual role the project would retain for the profiles once they had been developed.
I recall discussion that the profile of a person who had his own page on Wikipedia deserved a Notables template, but I don't recall any discussion on what the Notables Project (which I'm not a member of) would do with profiles to which anyone had added that template. So I"ve happily added a Notables template to profiles where there was a corresponding Wikipedia entry, thinking I was doing a favor. If it turns out I'm creating responsibility which hadn't been asked for, I'll stop!
Now for some groups, like Euroaristo (which I am a member of) , template + active management + a project email group means that everyone in the email group gets notifications of any changes to the profile or merge requests, which is a greater degree of active management than many might want.
It would seem appropriate that how and when templates should be used should be determined largely by the project, perhaps within certain broad parameters.
From that perspective, it would be extremely helpful to have a free-space page with a table on it identifying the template, the project it is associated with, when it should be displayed, who should display it (and who not).
Limiting templates to two would certainly keep profile clutter more manageable, and maybe promote collaboration among projects ("I'll trade you two German counts for a French duke")
