(This is meant to act as a sort of part II to my previous post. Simply some ideas which I had that I didn't include in the previous one to not take up too much of everybody's time.)
When I say roof turret, you most likely picture Roof-Mounted Red Lasers, Point Defense, Cannons, ETC. I thought though, that not every roof-mounted structure needs to be a weapon. We've already seen this with the Tractor Beam, but I thought I'd just share some more Ideas I had.
Solar Panels - An alternative form of Power Production, Solar Panels come in pieces that are around 2x3 tiles in size. The Idea is that they produce power at a relatively slow rate, at the benefit of not exploding when shot. They can be targeted like other roof "turrets", and would not need anyone to man them. Maybe some sort of cable system could be incorporated that allows them to directly power certain rooms, so that you don't need to put Generators right next to more important rooms.
Solar Kite - A 2x2 (maybe 3x3 or larger) room which deploys a small kite that flies above ships. It slowly draws power sending it directly to it's "base room". When the kite itself is destroyed with Point Defense or Flak it simply explodes, and the room it was tethered to becomes useless(?), but when the room is destroyed it simply breaks letting go of the kite. The benefit is the reduced volatility at the cost of being more vulnerable (kite) or simply producing less. I know this is functionally similar to the previous idea, but I figured I might as well mention both.
On-Board X-Ray - If I recall when battling an enemy ship, you cant see it's internals. I just think it'd be neat and probably useful to have a system visually similar to the Radar, that allows you to see into an enemy ship. If the Solar Panels mentioned earlier do use "cables" to power specific rooms, this would allow you to see which rooms they are powering so you can take our the right panels.
Rotating Thruster - A Thruster which could vary in size which can rotate allowing for more mobility and diversity in movement. I thinking it should only be smaller sizes though, so it doesn't fully replace having thrusters actually on or in the ship.
Disruption Field Projector - If Starfighters make it into Cosmoteer, like I said in my previous post, they'd probably need to fly OVER enemy ships. This structure could be a slow rotating device, similar in look to a shield generator. It would generate an electro-field that disables enemy starfighters allowing them to be targeted easier by Anti-Starfighter weaponry (PD etc).
These are all pretty basic Ideas but I just wanted to show how much value a "roof" section of the ship would have. Thanks for the read!