Currently, if there is a volunteer(s) dedicated to website work, the simplest way to provide and manage that is to give them Site Admin, which is much more than necessary.  If you were to poll your users,  I suspect this is what many people do.

If Site Admin isn't used, there are at least 4 other security roles that need to be assigned to someone in order for them to admin the website.

It would simplify managing users and user roles if there was simply a Website Admin role that gave them full control of the website.  You could keep the more granular roles if people only want some users to manage certain parts.

thanks,

gary