I don't use any of the navbars, top or bottom, in any part of the site; but I'm weird. Although, there's no reason to remove any of them, I know they are used and when sites have a lot of forums, one at the bottom is useful
Isn't that more the breadcrumb you are referring to? The navbar is up the top with dropdowns. I'm sure you could drop out the breadcrumb with a simple deletion on a per design basis. I think we have to remember this is the base product design, not the design upon sites uniquely.