Things I would LOVE to see in Sins:
Random events, On/Off selectable like pirates, things that could drastically effect large campaigns such as blocking phase lanes or making planets uninhabitable. The events can be what you like, Asteroid strikes, Alien invasions, Star collapse, whatever, just these kind of things would add to the whole experience. Maybe there are ally events also with ethical (which affects relationships) decisions that have an effect elsewhere such as economy, production etc.
More planet diversity.
On/Off selectable xenophobia so Vasari are more likely to like Vasari and hate other races and similarly accross all races.
Better missions from allies. How about I am attacking planet X in X minutes, please assist. And their happyness being affected according to the player response. Or "I need an idea what faction X is doing, please check them out for me?" which would mean a scouting mission for an AI who you share ship vision with.
How about a more fluid Ally happyness system. One where you can see the ralationships between all allies (perhaps with certain techs researched) and if you destroy ships or structures of an enemy X that another AI, enemy A, hates then the happyness between you and AI A goes up some relative amount, and likewise alliances with AI X would cause friction with AI A.
More diverse Planet development choices, think GC II but not as complex. Pretty sure I have seen screenshots in the beta with this kind of thing but I'd love to see it concidered again. Choices such as weighing up population with defence, or production or research. And ofcourse race specific super developments that are expensive and are then considered like an artifact in game play terms (all other players are informed and changing planet ownership changes ownership of the artifact/development).
An espionage tech tree that can allow the following techs:
The current ones such as phase lane monitoring etc. (Surveillance spies)
Alliance relationship and economy visability. (enemy leadership and governments spies)
Artifact visibility. (Planet spies) High level upgrades give hints to the defencive level of planets and perhaps some (lagged) visibility of fleet strength at planets.
Perhaps the espianage techs also include a constant overhead to keep and can be 'scuttled' at no resources returned but need to be paid for again with the same development time etc.