I was thinking that it would be cool with some battle fleet gothic style fighting in orbit and be able to offer ground support such as orbital bombardments or a teleport matrix. Then also have a vast interior so enemies could capture or invade vessels. Does anyone else think it would be cool?

In theory yes. In practice it would be difficult to implement, atleast the space battles since they would require different mechanics completely. Air support would be cool to have though, PS2 style.

Indeed space battles would probably be a pain to implement but basic air support would be neat

"Air support would be cool to have though, PS2 style."

well orbital could be easer to do with a hi cost resource beacon that will direct the bombardment.
the beacon can be turned off by another faction so needs 2 be defended untell the last possible moment

eldar can have elderich tempest
space marines can have a orbital
chaos ether same as sm but red or big ass melta style shot (thinking abadons planet killer style from apoc)
and orks get a big ass rok

as for air support would probably be simple enough

chaos can have the heltalon bomber and hell blade fighter
eldar phoenix and nightwing (dont like the hemlock or the nightshade)
orks maybe fighta bommer and chinork warcopta
and sm have there stormtalon and maybe the storm eagle

True enough, but the flying in space mechanics wouldn't be too different from flying on the battlefield. I believe Star Wars Battlefront 2 had that, where there were two ships and fighters would go from one to the other

I do believe the addition of aircraft would be cool indeed if its made, as you say, akin to Planetside 2.

http://forum.eternalcrusade.com/threads/space-combat.588/

I started a similar post about this. I am strongly for air and space combat support. You can't have 40K without them

Absolutely would be cool. If done, it would probably just be NPC call-ins like Call of Duty at first. Maybe post-launch they can actually have manned craft.

Yes, have it all coordinated by a commander located somewhere on the ship. Also have some form of escape pods.

Also, maybe they should add some sort of Deepstrike thing. Like a squad leader plonks a beakon thing down, and his squad can spawn on it (again, just like in Planetside 2)