I would love to see Sins 2.
As for features, I think adding in stealth units may be a good choice. With the Vasari's enemy approaching and the fact that it appears to black out all communication I think this could be a major theme for the game.
Another thing would be improving the economic options. Maybe you could have the option to raise taxes on a number of planets, which would net more income but make them more vulnerable to enemy culture. New specializations could be nice, I liked how Ironclad put in down sides to them so you were discouraged from specializing all your planets. Maybe one for research?
With the clamoring for a campaign I think Ironclad could at least have a series of scenarios, where the player is given special objectives. You could have one as the Vasari loyalists where you have to gather enough resources, while fending off enemies, or one as the TEC rebels where you have to cause damage to enemy structures and bomb their planets. Maybe put in special friendly and enemy units, like the former may have an economically oriented capital ship, while the latter could have a hard target destroyer. This could also help new players learn the game.
I've heard that voice acting can be a big cost for story based campaigns. Once you say you're doing a campaign players expect there to be a story longer than a few sentences per mission, and, from what I've heard, there are many who would want it voice acted. Getting good voice actors is difficult, and, from my limited knowledge, a lot of the people who want voice acting have quite high standards. I think we should be willing to moderate our expectations, as Sins has enough large maps to last hundreds of hours, and I think there is a tendency to expect too much. If there is a story based campaign I would recommend Ironclad to keep said story simple and focus on a few key themes. Focus on showing how the war affects the characters and keep the story focused.
What do you all think about expanding single player and the Sins gameplay? Should stealth be introduced and how should Ironclad handle a story if they were to go that route?