Yeah all respawns are too much. I once destroyed a vertibird and killed it's crew before i went into the water treatment plant only to see both respawned when I left the plant.
I strongly dislike that no matter how many locations I clear they will always be at full power soon after. It's like my character makes no impact at all. That is really unimmersive and has bothered me since Oblivion. I guess it is for those who just want to kill something and are not bothered if the world they play makes little sense but it is totally out of hand in Fallout 4.
Locations should change after they I went there killed everyone and took all the stuff. I doubt that they will change basic mechanics like this afterwards but if they are willing to put more work into this game than some DLC that takes place of the map then they should definitly consider doing something in that depardment.
Heck the minuteman are all about making the commonwalth save but in the end you can't do anything. I already suggested a whole system of gangs/ factions that battle for controll of locations and of course the option to join a raider gang in one of the countless suggestions threads. This could nicey tie in as "fifth" ending (not that there are real diferent ending) and "after the end" gameplay.