Why can't server admins bulk-import server-level blocklists of individual accounts, so that we could just take this Jimmy guy, compile all his alts and directly download/import those blocks to our server? You'd silence these people quickly and be able to coordinate to shut them down if that were possible.

We can import server-level blocks, but not user-level ones (which is why you hear so much online about server-level blocklists, and not personal ones).

But in cases where we have someone running around and creating an alt on literally every open-reg server that exists, it would be nice to subscribe to a list of these fools.