I'd like to see a planet killer ship - now that would be interesting!
We could also have a planet creator (I think you could create planets in one of the early Space Empires games).
I'm also fed up half way through each game - by the half way point I know if my strategy has won the game or not - so unless I start destoying all my own ships and insulting all my neighbours - its a given that I've one. Boooorrrrriiiinnnngggg.
I've even just abandoned games half way through as I know I've won.
I'd like to see something like the Borg - an outside, unpredictable almost unstoppable force that can cause wreck and upset the balance or power - especially if they start attacking the strongest players plannets. I'd also like to see all the other civs start to realise that the games almost over for them - and for them to abandon their in fighting and start challenging me - perhaps even working together.
Both these things would turn my walk in the pack 2nd half of the game into a frantic bid to try to develop technologies and ships capable of eventually stopping the Borg-type menance, while trying to fend of or desperately make peace with the other races.