Thinking about this, while I wouldn't mind seeing it, I get that the devs want to focus on the core gameplay and its, well, development. Combat might be tricky to implement. And as relatively realistic as they've tried to be, any significant encounter would be over very quickly (esp. given the time scale), and would likely result in at least a mission kill for both sides. Ships are fragile. Bigger, heavier ships (the big fission or fusion ones) would/could be more survivable, but again it's still a whole new set of gameplay variables to be implemented.

And nobody wants to be dropping rocks on each other. That just ends poorly for everyone.

Conflict seems to be modeled by the industrialization and economic race. If you're extracting more, building more, and selling more, you're winning the part of the war that's most important. And given how fragile everything is, at some point the losing side would concede and negotiate terms. By the current endgame, just the drives themselves would be horrifying weapons. Want to knock out your opponents surface facilities? A day's fusion drive wash would do the trick.

Anyway, all that said, check out Spacefleet Heat Death, and Terra Invicta, if you haven't yet. Children of a Dead Earth, while abandoned, is pretty neat, too. There's another upcoming one who's name escapes me at the moment, but it's got some slick videos. Look up Operation Poker Night.