Those were my reactions, too! The one thing that I want the most whenever I have to jump out of the CSS per-processor world and write regular CSS.
It is worth noting that in SASS you can already refer to parent elements as they have shown with the `@nest` rule (apologies if I misunderstood what you said and you already know this). I do prefer the more verbose `@nest` syntax though, as the intention is clearer.
I'm sure there's a reason here that I'm not seeing, but it feels like it's being different for the sake of being different to me-- requiring `&` even in the simple case where you're combining them with the descendant combinator (plain space), but then also requiring `@nest` in any situation where `&` is not at the start of each selector.
SASS takes the opposite approach-- there's an implicit `&` at the beginning if you don't specify it elsewhere, and it can appear anywhere (i.e. the example `:not(&)` does not have to have anything like the `@nest` syntax in SASS).
It is worth noting that in SASS you can already refer to parent elements as they have shown with the `@nest` rule (apologies if I misunderstood what you said and you already know this). I do prefer the more verbose `@nest` syntax though, as the intention is clearer.