Currently Epiphany allows to block cookies from all sites, or from none at all.
But even people who generally do not want to accept cookies will usually have a
few sites, like forums, Wikipedia, Bugzilla, where cookies are required. They
cannot use these sites, currently, without allowing cookies for all sites. It
would be nice if it was possible to allow cookies for selected sites while
maintaining a generally policy of non-acceptance.

Firefox solves this by allowing the user to define "Exceptions" to the cookie
policy, which are valid for a site and can be of the type "Allow," "Allow for
Session," and "Block" (the latter is useful if you generally accept cookies but
want to disallow a certain site).

Epiphany should have a similar option.