In the other topic I posted about some possible "space terrain." Perhaps I could be more specific about possibilities with that for this topic. I'm not really meaning battlefield-wide terrain, but rather medium sized areas with special effects. Maybe there could be a mapwide nebula, but a mapwide minefield would be awfully silly (and painful).
I said there could be minefields, doing damage over time while moving through it perhaps depending on ship size and current movement speed. There could anti-shield minefields too. While going into a minefield usually doesn't sound like a good idea and might essentially be a brick wall, it might be worth it if you're on the run and your ships are less susceptible to the field than theirs. There's also the possibility there's something on the other side/inside it that you want to get to that's worth the pain.
I also said there could be nebulae, acting to contrast minefields. While minefields do damage to ships as they pass through them, nebulae could change how things act inside them instead. Not just ships, but maybe shots as well. Perhaps ships inside one nebula would be slowed down, and another nebula could increase damage taken for inside it. But their effect doesn't have to be strictly negative, and nor does each nebula only have to have one effect. Maybe there could be a nebula you come across that slows (or speeds up) shots that pass through it, and it also amplifies the damage of those shots. There's really a lot of possibilities with this, I think.
Oh yeah, I initially posted the nebula idea for hiding ships in since obscuring view was said to be unfeasible. Maybe some could do that. Or maybe they all just do that... There could be special effects, whether from certain pilots, ship types, tech, or whatever, that allow seeing further into a nebulae than normal - or just reveal them entirely. Could also be the inverse, with effects that make your "nebula sight range" go down, or maybe even going to the extreme of temporarily being unable to see ships in a nebula. Could even be ship types that can't see in a nebula by default.
Oh, and maybe there could be colored mini-wormholes that allow instant transportation between similarly colored wormholes. Maybe even allow firing through them! Possibly restrict usage based on ship size, so you might want to deploy some ships specifically to take advantage of these; or predict your enemy is going to use the wormholes, and position yourself to prepare for it. Could have different versions of these wormholes, like maybe unstable ones that only work for a few ships before collapsing, maybe ones that are delayed and take time for ships to emerge from, or maybe even ones that are one-way only! Could compound multiple effects on one set of wormholes as well...