Okay, a couple more suggestions that occurred to me out of the aether this morning. Please keep in mind that I have no idea how plausible these are from a coding standpoint; they may be outside the realm of possibility, in which case oh well, it really was the thought that counted.
New race: Privateers. A race with possibly cheaper ships, a few fairly wow! kind of racial weapons/modules. Here’s there real racial schtick though: You can deploy their ships for any other race as well as on their own. However, in keeping with their mercenary nature, Privateer ships come with a proportional cost increase when deployed on behalf of someone else (maybe a 25% increase?) - i.e., you’re hiring them to fight your battles, so they get to set the price. This would take a metric buttload of work, since you’d have to make sure that the Privateers would be worth deploying in someone else’s fleet while making sure they weren’t completely overpowered on their own. Probably this would have to be a few really impressive racial modules offset by some sort of serious handicap.
New hardpoint module: IFF Scrambler Beam. An improved version of the Guidance Scranbler Beam, it functions much the same (perhaps with a slightly longer range or faster cool-down). However, a missile hit by an IFF Scrambler has a small chance to reacquire its targeting - on the ship that originally fired it. Makes close-range missile fighting dangerous, since at long range you have a better chance of your own missile running out of gas before it gets back to you.