Yeah the ability itself is fine IMO. It is very much a pro gamer™ ability though. Depending on how it calculates there may be ways to seriously cheese it. For instance, if you use Darwin to pop +2000 science on a 4 hex natural wonder, which in turn grants you your first tech of the era, will you then get +4000 culture or does the bonus only count your per turn science?
Oh man that would be awesome as a cheese.

. There's only six triggers throughout the game, and there's not much strategy involved in deciding when to trigger a tech from a new era because playing as Korea you're already focused on Science and Seowons, which means your Science is likely to be close to optimal at all times anyway. So it all seems to boil down to "can't forget to slot Rationalism / finish that Seowon before completing the new era tech." It's so dull. Will be looking forward to a rework;