the thing that bugs me most is when a pirate sneaks up behide you and takes you out in a few shots.
Would it be possible to have like a warning device which tells you when an enemy is targeting you?

Two items already exist for this purpose, they are called radar and intuition. Learn who the pirates are, press "u" the moment you enter a sector to see who's in. Constantly press "x" to target the closest ship. Keep and eye on anyone 600-700m and closing in fast. Just stay alert and look on your radar for threats.

Instead of pressing 'x' all the time, make the keyboard config smarter. Place the 'nearest enemy' button to be the mouse middle-button. It makes is much easier. Also, u might want to set the mousewheel to cycle thru "items/enemies in front"