As you said this is a matter of test! Complexity hidden in a template rather than more simpler templates. Let say that this has been the historical way of doing it and I'd prefer that for the standard part, we keep it for the pace of consistency.
You are right that there are many variabiles. Too many, I don't know, What's the threshold? I am not aware of a particular price related to the number of variables. There main advantage is to abstract the way we are implementing things: a variable provides a feature but the site-specific templates have no direct link to the way this feature is implemented.