well, first sins ships CAN move in three dimensions, its just that the default settings dont have this, and you have to edit the hotkeys a bit to fit it in, but its there. Rarely even the ai uses the third axis, I have seen pirate fleets go OVER planets (really, over, not through, like fighters and bombers do)
other then that... for sins of a solar empire 2... a graphics upgrade of that magnatude would be nice.
Although, really, for the game right now... even a few (minor?) upgrades would be nice. (if possible) For example: I really dislike it how the autocannons and stuff on ships dont swivel, and the muzzle flash points straight, no matter which direction the gun is firing. A second pet peeve is that, while most ships and objects are nice and solid, fighters and bombers can pass through planets and other ships... and third, while the ships actively attempt to use the z axis to keep out of each others line of fire (which is awsome)... your ships will still sometimes fire through eachother without causing damage... ships should hold their fire or pick another target if other ships are in the way... which would of course make formations, and ship positions just a bit more stratgic... and more importantly, nothing ruins a space battle screenshot like a laser beam traveling through a ship. and as far as physics go... and while the physics of ship movment is normally great, if a ships engines are disabled, it should still maintain its momentum, instead of stoping almost instantly... and a disabled, stationary ship should gain speed towards the center of the gravity well... and other such gravity, and newtonian effects and stuff would be nice, but prolly not possible. [/spam]