I've run a test in Hyades Sector AA-P b6-4 (21.82Ly)I think there may be a quite simple way to restore combat which could be woven quite easily into the notion of effecting withdrawal by capturing bio-mechanical material—make Thargoid Hearts worth as much as a few dozen Research samples. As I write that, I notice that I know not the effect of capturing a Thargoid Heart at the moment.
Before my activity: 0.000000
Cyclops kill: 0.000351
Cyclops heart sold to rescue ship: 0.000351 (taken at 29mins past the hour)
Doesn't look like hearts have any effect.