So far I didn’t attack havens yet, mostly because I want to explore map at the first and complete other missions (to be fair, I want to have good relations with all factions for their quests and research trees).
I know that when there was ODI, attacking other factions was a choice for such reasons as “nothing personal, it’s just busi… for saving a world” or “I hate you and you are already doomed, so I will strip off your resources”. It looked like backstabbing, but consequences for losing haven could be reversed.
Now with HPC prosperity of havens becomes more important, and for me aggressive actions against any of them are looking like shooting yourself in the foot, because it can lower their chances for survival.
I’d like to ask your opinion on this subject. Maybe raids really don’t matter much and can be exploited, as it was mentioned in other topics? Or attacks on factions became an obsolete mechanics due to later changes?
a) Quick resource raid - you used to get a lot, havent tried recently, like 1000 tech or 1000 food or 1000 materials depending do you raid science/food production/factory. Raiding it once I dont see as really taking their survival chances down. At some point anyway Pandorans will be way stronger and develop faster then them and your ability to defend certain points will be matter of their life and death
b) Research theft - Mechanics that give you all once aligned nulls all efforts why to steal early. Since you need to develop squad I find reverse engeneering from mission obtained weapons or by taking it off recruited soldiers way better mechanics, even they steal some research time from me. Stopped doing it as often as I did, maybe one early theft. Earlier their research ceneter would need a repair, but I dont see overall fraction development slowed down.
c) Aircraft theft - I find this as necessity because it gives early edge to develop 2 plus squads, explore way more, go to special missions and be able to defend with other ship. Plus its not the cost of aircraft but long manufacture time that makes it necessity. Does it harm them? They anyway use it just to attack other fractions and I soon see some airplane appearing at some other heaven.
So I believe mechanics that harm them is not so well implemented to worry about it, neither their survival is made such priority.
Most importantly, all diplomatic relations get mended by destroying Pandoran Nests. 1 harder raids is 3 nests, so it will take time and delay alliances - but its repairable if you raid them in turns and dont look one as strict enemy. OR you can say one is the enemy - and keep living of it (I prefer Anu 
Also, some question marks have small choices that also matter in boosting relations plus 4,5 …