After the viewing the following video https://www.youtube.com/watch?v=M40JOsLd--s, I have to say that the environment looks pretty ... boring? No, thats not the right word.. But it could use some more life, or interaction if you prefer, as its not all that exciting, though that's my personal opinion.
So, how about introducing the levolution concept? Though I'm not sure whether that's possible using Unreal Engine 4. But my idea is as the following.
The invironment includes a lot of asteroids and debris from ships. What if we would make this interactive? As the battle progresses there could be random events like a small meteor or debris shower. Getting hit by such an object could kill smaller ships or significantly damage the bigger ships. It would make the map a bit more interesting and even more strategic, as you'll have to be aware of your position and environment.
Just an idea, of which I'd like to know your opinions :)