Yes, single-instruction operations would be fine, but if you're writing multithreaded code you are probably doing things that the GIL doesn't protect all the time. Like dict-updates on classes that implement __set__, or `if not a[x]: a[x] = y` sorts of two-phased checks, or just like, anything else. You can't get very far with global state without reckoning with concurrency, GIL or not.

I assume that a change to relax the GIL will both allow you to opt-out of it, and allow you to use locking versions of primitive data-structures, anyway; it's not like it's going to just vanish overnight with no guardrails.