Right now, I can't really threaten an empire. I can tell them to do something - make peace, "donate" money to me, give me a system, etc. But I can't say do X or I'll launch a trade embargo, or I'll attack you, or I'll make an alliance with the Altarians, etc. I'd like to be able to threaten the AI and it consider the impact of such a threat in its decsion to say yes or no. I realize this might not be easy, but it would make diplomacy more interesting.
Have you given any thought to this?