Sorry, but I disagree with you.
If you want to make the case for specific settings that could be moved to site settings feel free to argue why they should be site settings instead of config settings. I will discuss them on a case by case basis.
But in general I have good reasons why some things are not site settings and when I review the app settings I only see a few candidates where I might consider making them site settings. I already have a place in the database where I could store additional site settings if I decide they need to go there.
New users should just accept the defaults in most cases and only make changes from default when they understand what the setting does.
Actually adding more settings in the UI is going to present more confusing choices to non-technical users and make it less user friendly.
Many of the settings need to be enforced globally and not be allowed to differ in different sites in a multi-site installation and config settings is the best place for that. Someone who can edit the web.config is considered a server admin, it may not be desirable to let site admins change some settings.
I will say that I do need to review them and its possible there are a few no longer used settings that could be removed.