I've now played through a winning game with all of the factions, and the first time I played with the science people, they felt a little weak. So, having not really understood observatories, I decided to aggressively place them early in my second playthrough.

However, they cost me upwards of 200 gold to make, and yet EVERY single other faction, including one I had 4 different treaties with, aggressively destroy them despite our diplomatic relations (even if they are in neutral territory).

This should probably be toned down a bit, especially early. It's basically impossible to maintain them because they are so easy and fast to destroy, cost me a significant amount of dust, and even people who generally love me will destroy them just because they can. You can't even defend them because the AI has no problem sitting in a space directly next to you and destroying your observatory with no diplomatic repercussions.

It's a relatively small thing, but it should be put on the list of things to look at.