Really enjoying this game, just purchased it after having been playing it in the browser for a few hours the past couple of days. There are 2 things at the moment which I think could improve it for me personally, the ability to unlink slipways at some point and being able to zoom out and get a better overall picture, or have a map you can open. Another feature that would be great would be preset maps so that it's not so random, having a defined goal or missions goals per level could be good too. You've probably already thought of all this but just thought i'd give my thoughts. I really enjoy the passive style of the game and the addition of military would probably ruin for me. Perhaps being able to choose a passive mode would be good too.
The only opther point I would add is longer play times, it always feels like the game is over too quickly. Maybe extended maps with open ended games (game ends when you reach a goal rather than time limit) so you can explore further would be cool too.
Getting pretty addicted to this despite what I said above, been filling a lot of my spare time between work etc. Getting some nice results for tech and happiness but I still feel like the end result is quite dependant on pure luck. Sometimes you just can't do anything with the planets you're given... Much like real life I suppose. :)
"the ability to unlink slipways"
I'm not sure about this. It would change the gameplay a lot.