I'm loving Sins, but I don't think I'm alone in my disappointment over the diplomacy system. For a game that's supposed to be 4X, the diplomacy seems rather weak and oftentimes silly. I'm really hoping the devs will release some major changes to it soon, and I wanted to voice what I thought needed changing.
Firstly, I hate that there's no clearcut way to see who is allied with who. In a world where ships can break light speed, it seems weird that you somehow can't get information on alliances. I really hope the diplomacy screen would get a new tab to show everyone's relationships with each other. Even better, I'd like to see an alliance system implemented, so players could invite each other into alliances or request entry into already formed ones. This would make things so much more clearcut as to who was allied with who.
Most of the other changes I'd like to see are in respect to the AI diplomacy. Frankly, it's silly for the alliance who I have just beaten half to death to order me to attack my ally as a mission. Why? It makes no sense.
I have no real problem with the mission system, I just dislike how silly the requests often are. I think firstly, an AI should never make a mission request if you are at war with them. Instead, if you are at war, the most they could request would be a cease fire. If you have a cease fire, they could request that you join their alliance or request to join yours. Only once in a true alliance with you would the AI attempt to make requests.
Even once the AI does start giving you missions, they should be realistic based on your power size to each other and not be related to assaulting enemies. Instead, I'd rather have it so that a larger empire would request money as tribute from a smaller empire. Meanwhile, the smaller empire wouldn't request tribute, but would request fleet support, but only defensive fleet support.
Furthermore, a smaller empire should never openly turn on a larger empire. If it is never getting support from the larger empire though, it should join another alliance. If the larger empire isn't getting tribute from a small, weak alliance, it should turn, but even then only if it isn't under assault.
I think this setup would be a lot more realistic than having that guy I despise constantly telling me to pay him and bomb my ally when we don't even have a ceasefire. The only other change I'd like to make would be to let human players send these requests to both AI and other humans in a formal system. That way I could make it very clear to that tiny little empire just what I wanted and get it quickly.

So, anyone else have other suggestions? Let's get the ideas flowing.