Shameless re-post from the 3.04 thread, which I will continue to re-post every patch until I get a dev response of "thanks we'll think about it" or "thanks but no thanks, we like it the way it is".
Can you please put in some code that destroys all (or all but 1) existing pop when a planet is conquered by an incompatible civ?
I would define "compatible" as Carbon/Aquatic with Carbon/Aquatic. Synthetic only with Synthetic, and Silica only with Silica.
It is slightly rediculous, immersion breaking, and game-breaking that a race that spends so much time and resource to build more pop gets unlimited instant free pop conversion if they take over a meat planet. It is only slightly less rediculous (but more amusing) that when a meat race takes over a synthetic planet, the robots all start having babies.
(I almost want to say, "for £5 I will not interrupt this patch!")