It’s not like immutable contracts don’t get used to rug. Real contracts need renegotiation all the time, because they need that kind flexibility to actually work. Conditions change, consequences of the wording crops up, that sorta thing. It’s impossible to foresee every possible scenario before making a contract after all.
I don’t see how smart contracts should be any different. Immutability is a trait that contracts shouldn’t have, and I think the idea that they should be comes from a misunderstanding of how contracts are actually used to screw people. It’s not suddenly changing the rules that gets you, it’s obfuscating verbage intended to confuse and mislead the target. Which is something that a good lawyer could help sort out in court, or at negotiations.
Then again I only use this stuff to buy weed so ¯\_(ツ)_/¯