Replayed as a fleet officer this time round and boarded myself a Battleship. Joined sector invasions and the played around with the fleet combat. Is there anyway in the game that allows me to actually buy a battlefleet of ships instead of just flying around in the Battleship?

Also, any ETA on when the exppack is coming on GOG? Carriers are in the exppack I assume, I hope they are able to fight at long range all the time and deploy the fighters from a distance.

Hmmm, that's unfortunate. Be waiting for the exppack then.
The game deserves alot more depth to make it stellar. It's good now but needs more options both in the general gameplay and combat sections of the game to make it awesome. More ship equipment would be great instead of seeing the same stuff over every planet. Combat like MOO2 would be great. Bigger ships should have more guns and ways to attack instead of just a dmg increase, stuff like that. Being able to own a fleet would also be good.

Yes, I'd second all of this. The lack of features is probably due to the very small development team. Actually it's only Niels Bauer and some hired independent freelance artists. As of now there's no statement that the expansion contains fleet building and I haven't played the beta, so I don't know if we'll get it.