So, I was playing Totalwar Atilla and I got an idea that would (to me) feel amazing to have in GalCiv

So, I want more diplomacy options, and I think a massive diplomacy patch is coming. So here's what I believe would be great to add to the game

Conquered empires. I would love to have the option to conquer an empire, not by taking over their planets, but by forcing them to do what I want. Pretty much, whatever diplomacy I have to other civilizations they have. They get to research their own tech, build their own ships, etc. But, they fight whatever wars I'm fighting, and I get a percent of their income. 

For example, a benevolent race would probably avoid this, or do it to over watch a more hostile race like the Drenin. Make sure they stay out of trouble and don't kill people who don't need killing. 

A pragmatic race would use them to fight their wars and as new more lucrative trade markets similar to how the America's were used in the colonial times. 

A malevolent race would see this as an opportunity to enslave another race, make them fight for them to get more slaves, and raise the tribute to punishingly high levels. 

Of course, this system would need a way for the conqueror to maintain power over the conquered. So, have a few diplomatic options such as assassinating a rebel leader, making an example out of someone who isn't happy with the system, and such, but, also to have things such as educating the conquered on the 'right' culture and traditions, using propaganda, and paying off government officials (exploiting whatever corruption there may be)

Now, the conquered should also have options to get free, or to play along. They could start a full rebellion, or slowly feed a smaller scale one (such as hiring pirates to harass the conqueror, of course in secret). Or they could do what the conqueror wants and persuade them into lowering taxes and instead of being under them, work your way up to an actual alliance among equals.

Now, how the actual conquering can happen. Most likely, military strength. Someone much stronger militarily can threaten a weaker race into this, like "Become our puppet race or we will exterminate you" type of stuff. But there should also be a way to do this more "diplomatically", like assassinate and corrupt the right officials to pass a bill giving away their Independence and such.