I'm not sure I actually want that. At minimum, I don't want to always be able to know all alliance all the time (well, I want to know, but I don't want everyone else to).
Really, I think it should be information that you have to work for somehow, be it through research or diplomacy or espionage. Stealth alliances, while dirty and underhanded, are a vital part of war and taking them out would make the game lose the most effective/realistic little bit of diplomacy the current version of Sins has.
Edit: Whoa! The dev changed his user icon (and maybe screen name) while I was typing my reply. Weird.