Adler17 said:
In ww2 both sides used captured enemy "units" like German T 34 tanks or a Greek destroyer which became ZG 3 Hermes. So it isn´t unrealistic. The chance this happens should be 10% or so on the other hand.
Adler
Yes, but in civ, these would be units that the capturer could already build, i.e., both sides cold make destroyers and tanks.
The part I'm argueing most strongly against is the idea that a backwards civ that couldn't build tanks on their own could capture some instead and then immediately know how to repair them and use them effectively against their former owners.
If you were far from being able to build tanks on your own, you wouldn't have the foggiest idea how to work a captured tank: not only repair and operation, but basic maintenance and fueling would be problematic. On the other hand, if you were close to being able to make tanks yourself, you'd be much more likely to turn over the captured vehicles to your scientists so they could take them apart and figure out how they worked, giving you a leg up on your research.
Actually, that brings up an interesting point. Currently, a tech get easier to research if more civs that you have contact with get that tech. Perhaps a better way would have it depend on
use of the tech. In other words, if your neighbors know horseback riding but never build any horsemen (maybe they don't even have the horse resource) then it shouldn't help you research horseback riding faster. On the other hand, if they build wave after wave of horsemen and send them to attack you, your people will get a lot of experience fighting against horses and will probably have an advantage when trying to figure out how to train horses on their own. They might even capture a few in combat, which would help them out.