Essentially, I have plans to do something STNC-unique with salvage but just need to work out the mechanisms. A lot of tech isn't allowed to be salvaged though, for legacy balance reasons.

I do want to revisit this.

I understand, but... I must say that some ship blueprints are very unbalanced and AI will use it to its advantage. Lets say Dagger, this ship has no additional armor, so when you invent shields (they replace polarized hull) there is no armor at all, not to mention that some ships are horribly slow and artillery tactic (-20% speed and not only in combat outside of combat too) will made them even more slow in the end making them fly like a snails.

This problem don't affect much major empires like Federation, Romulans or Klingons who has multiple ship blueprints to pick, but it can be deadly for other empires like Remans, Betelgeusians or others. And believe me, AI can by nasty in this new updates and can pull very tricky moves like realasing vasal or suddenly break all treaties of neighbouring empire to force your fleets to MIA status only to not loose an important war.

As I said, I understand that you wish to keep this for legacy balance, but... in some cases either the combat balance need to be adjusted or some partial or less significant blueprints should be salvagable. Lets say as example Klingon Borghell or Brell, after all they drop this birds here and there and crash them whenewer they can even in the Delta Quadrant (Voyager episode);).