I would suggest being able to have the option when purchasing a ship to either trade the ship (current ship buying) or add it to your fleet and if you have it docked on a planet you have to pay a fee for it staying there. You can also store other ships in your fleet in your ship hangers if there's space I.e 1 hanger 1 small ship. This will make it more fun and if you go for the pirate/criminal side of the game you can have a large transport ship which carry a small agile fighter to raid ships.

Another thing is that when you kill a crew on a ship you can raid it after and it stays adrift.