A good answer is "I rape and murder exactly as much as I want to, which is none. If eternal hellfire is the only think keeping you from doing those things then I hope you never lose your faith."
I only pitch it to people who already play MMOs. It's a massive time sink, and very heavy with cutscenes. Sometimes the story gets really slow (like basically doing chores for people to convince them to help you save the world) but at other times it's absolutely incredible. I agree that the 4th xpac is some of the best writing ever.
As for spoilers in the game, you should be pretty safe. The game itself will take you through the story linearly and the community is generally very respectful.
You can play the base game and I think the first expansion up to level 60 for free. Be aware that it is an MMO, and they've kept most of the content that they've added in the game, so it's pretty daunting starting out.
Changing? Zergs have run servers since the first day I played almost 10 years ago. Small monuments are war zones the first few days of wipe. I don't think that's changed much since. Rust has never been cozy on any server with a population.
A good answer is "I rape and murder exactly as much as I want to, which is none. If eternal hellfire is the only think keeping you from doing those things then I hope you never lose your faith."