Limiting radius ala 76 is technically less creative than what CE has. Basically, a majority of players on fallout will build a meta build of cubes. It is a video game, and there will always be those things.
CE only limits based on “unradiable” guidelines, like undermeshing, certain spawns, areas that would remove the the seige mechanic in theory.
I think the issue lies in how CE was structured. It is structured as a survival game, that has leaned more on surving against other players than the enviroment. Hence, like @Mikey has stated, the purge needs to be the dominant cleanser for official servers. And TBH, NPC’s should be be more aggressive as well. Make me worry when i go thru a camp, even at level 60 
Also, as far as Thrall AI against purges, i think we sometimes get caught up in the idea that if i have thralls, the purge should be stopped. Any other outcome is becasue the thralls didn’t function properly. But i have had 2 experiences where thralls worked as intended, as helpers, not as unbeatable shields.
1st, was on a tower base, purge of gorillas spawned inside base. The archers went to town, but i still had to attack as well.
The other was exile dogss attacked, and i had one berserker equipped with a trundeon, and TOGETHER we subdued it (but still know legendary black smith
).
Is there some tweaking to the AI yes, but to say they are useless is also fiction. They are what they are, and if depending on them to stop a purge by themselves is ones stategy, then the strategy is whats broken.
The only flaw with thrall AI is maybe the offline purge. I would rather see the purges happen when you are online. Maybe if your number comes up when you are offline, it stacks instead of attacks. so when you are online it will trigger automatically, and that is how you get harder purges. And once triggered, it completes its cycles, whether you log off or not. Just my humble opinion.