Suggestion: Reduce the negative effects of D-mods on lower tech ships, with midline getting a small decrease and low tech getting a moderate decrease (adding note: a blanket reduction, different from the upcoming hullmod for special ships).
Reason: When you think low tech you think rugged, reliable. Something that's not cutting edge but will keep working when battered, like an AK for rifles. But right now, lower tech ships aren't any more rugged or reliable than higher tech machines, being affected by severe damage as much as them. Making D-mods less damaging the lower the tech level would help solve that both from a gameplay and "feel" perspective, giving lower tech ships the "ol' reliable" identity they dearly miss. And this should be an innate feature - not some "character skill" that you're pidgeonholed into and is detached from the ships.
For numbers (how much reduction per tech level, are the base numbers increased or not so they're not ignorable), that's up to the dev. Pirate fleets may need more D-mods per ship on average to stay "weak" if that's their place in the balance, but that's simple.