I know this is off-topic, but I couldn't find a discussion thread for idiology tenets, so I'm gonna post this here. However, please feel free to point me in the right direction.
Long story short, I believe that Lebensraum should be changed into something else like Territorial Expansion or whatever. Why? Even though the concept came into existence in German history during the phase of imperial colonization at the end of the 19th century, it was taken to the terrible extreme by the Nazies during WW2 and that's what it is essentially known for since then. Here's an excerpt from the Lebensraum wikipedia page which sums it up quite well:
Following Adolf Hitler's rise to power, Lebensraum became an ideological principle of Nazism and provided justification for the German territorial expansion into East-Central Europe. The Nazi Generalplan Ostpolicy (the Master Plan for the East) was based on its tenets. It stipulated that most of the indigenous populations of Eastern Europe would have to be removed permanently (either through mass deportation to Siberia, death, or enslavement) including Polish, Ukrainian, Russian, and other Slavic nations considered racially inferior and non-Aryan. The Nazi government aimed at repopulating these lands with Germanic colonists in the name of Lebensraum during World War II and thereafter. The entire populations were to be decimated by starvation, allowing for their own agricultural surplus to feed Germany.
Hitler's strategic program for world domination was based on the belief in the power of Lebensraum, pursued by a racially superior society. People deemed to be part of inferior races, within the territory of Lebensraum expansion, were subjected to expulsion or destruction. The eugenics of Lebensraum assumed the right of the German Aryan master race (Herrenvolk) to remove indigenous people they considered to be of inferior racial stock (Untermenschen) in the name of their own living space.
As you can see, this is as bad as it gets when it comes to Nazi idiology. I simply don't think that such a concept or the word alone should be used lightly in any game since this is easily in line with concepts such as Endlösung (the "final solution" to the so called "Jew questions" -> total extermination). Imagine if you implemented that as a tenet, or Holocaust for that matter.
However, if, for whatever reason, people want to stick with it, the bonus and description should be changed to reflect what's actually behind it: Extermination/Deportation/Enslavement of indigenous people reduces a conquered city's population to 10% and each conquered tile creates a food and production bonus for existing cities or something like that.