I think we need a Sins-2, too.
A Sins-2 that would be truly multi-threaded. They could add another race or two to the game and more planet types in addition to some sort of a cheesey campaign. Or better yet, include some sort of a campaign editor engine--let enthusiasts produce free custom content for your game.
The game could also use an online multiplayer tutorial to walk players through setting up Ironclad Online accounts and whatnot. I also think that several improvements could be made to the user interface and I'd like the ability to press a Function Key and pull up a chat log of all in-game chat. And before I forget, allow custom maps and mods to auto-download and add built-in voice comm.