Really? I have almost the exact opposite opinion of it. If anything Pin validated the construction of Rust the language and it's approach to structuring types i

Really? I have almost the exact opposite opinion of it. If anything Pin validated the construction of Rust the language and it's approach to structuring types in the standard library. We got to express something at the type level without implementing it as some kind of custom language feature. It's complicated, but it's describing a complicated problem so the complexity is inherent. And luckily, most users will never have to interact with Pin anyway.