Rust is nowhere near the complexity of Scala wrt. seemingly arbitrary high-level features. There's a low-level, systems programming featureset that involves quite a bit of complexity but that's also less arbitrary when comparing across similarly low-level languages.

>If it slows down Rust development it's not pragmatic.

I truly don't understand. If you don't want rust to become complex, you don't want it to "develop" fast anyways. Unless you mean you think it will be slower to write code?

> And if it creates a cultural schism between full commitment and pragmatic approaches, it's also trouble.

Zero clue what this is supposed to mean. WTF is "full commitment" here?

> Remember Scala?

Scala, haskell, and others are high level languages in "academic terms." They have high levels of abstraction. The proposals are the opposite of high level abstractions, they instead formalize very important low level properties of code. If anything they decrease abstraction.