Geoff the Medio wrote:
It's possible to tweak the power of tech copying when invading planets by not giving the whole tech instantly, but instead giving progress towards developing that tech. Much like espionage, techs probably shouldn't be completely stolen or not on a random chance... Instead, capturing a planet with some buildings you don't have the tech to use or produce might give +X or +Y% to your empire's progress in researching that tech. Or, just owning a planet that has a building on it that you can't produce would give +X or +Y% per turn to that tech, possibly increased if you set research focus or have archaeology techs or a reverse-engineering species pick or tech, or similar.
Ignoring the issue of suddenly dying "cyborgs", i'd lean toward something like that.
Something like this: (numbers are FPO)
If you capture a planet with a building you can't build, you get +50% research toward that tech. If there's no such building, you get +25% toward the tech that you don't have that they do that is of the lowest RP value. That would boost the strategic value of capturing/defending buildings.
Reverse-engineering tech/picks could apply-- though i think it would make more sense as a tech. It would be kind of annoying to need to settle a particular planet with an otherwise unfit species just to get the retro-engineer bonus for a while.
RPs per turn of captured buildings might be more realistic, but continually require attention via SitReps, or some probably fiddly addition to the research screen. I think it's better to provide whatever bonus all at once.
EDIT: should prerequisites be considered in calculating what you can steal?