More critical to use is that on the login page, it offers to email a user there password. But this will never be possible on our setup.
I'm not sure how dokuwiki determines if there is email support. But I would like to be able to set an option that specifies if email support is available and hides it accordingly. If it does this already then I guess this is a bug on the login page to cause this to be hiden.
Most or (all) things you ask for can be disabled through their own config options or the disable actions option.