-Add more objects into battlemaps (since they are larger it can be scaled a bit better) such as dense asteroid fields, planetary bodies (with gravity and sensor implications), and perhaps denser nebulae which lowers sensor detection range.
I definitely agree with this one. Asteroids move very randomly, without much of an impression that they're at all bound by gravity. That, and they're too small and ineffectual. Asteroids can get REALLY big. Even if you assume a warship like the Paragon is three or even five kilometers long, there are asteroids large enough to at least serve as cover-- asteroids that would most certainly annihilate your ship if you flew right into them. I disagree with having planetary bodies or nebulae that lower sensor detection:
Planetary bodies: I don't feel that a planet would fit on the scale of the combat that is taking place, and trying to apply locational gravity on a 2d plane is wonky enough on the overworld. I do, however, think that fleets ought to be able to fight in high orbit, which could create cool visual effects like a ship's hulk dropping into the atmosphere as its orbit decays, burning and breaking apart (or not, they could just make a crash landing). It could also create new combat conditions, like having to fight an enemy fleet with planetary battery fire harrying you at the same time, as well as maybe new gametypes, like troop recovery, or delivery.
Dense Nebulae: Nebulae are stellar bodies on a galactic scale. The action in Starfare is intrasystem. The existence of nebulae that can slow you is odd enough, in my opinion, to render the idea of even denser clouds of gas slightly silly. However, fighting in the upper atmosphere of a gas giant WOULD make sense and would be
super cool.