You used to be able to see the extent of other empires as soon as you met them. While it's cool that they're shrouded a bit more now, it causes some gameplay problems. The biggest one is that it's not possible to fabricate claims on more than a few of their systems before war starts because you can't see them. You can make the claims once the war starts and your ships have started rolling in, but it costs significantly more influence to do this. Is there a way to map other empires, perhaps with an intelligence operation? I haven't seen anything so far, but I haven't played with the system extensively yet.