Here are some more ideas for the new game.
1st SHIELDS one of the things I hated most about HW1 was the fact there were no shields.
2nd Customizable ships like in Warzone 2100 or Alpha Centauri.
3rd A.I. that takes advantage of the fact that your fighting in 3 dimensions i.e. have then circle you and attack from behind or have several groups come at you from all different directions.