> Rust's lack of a REPL wasn't just them ignoring an important innovation, it was them choosing to not implement a feature that they know their primary audience won't use
Rust moving away from its more ML-leaning beginnings is a downside, to me at least.
Sure, but it was a conscious choice to do so, and Rust is actually a terrible example of a language that doesn't provide anything new.
Rust managed to normalize higher order functions in the systems space, provide a compelling answer for high performance memory safety, and mount the first successful assault on the C/C++ duopoly since C++ was conceived. That's a pretty impressive track record for disruption, and discounting it because it doesn't have enormous groundbreaking ideas and it doesn't have a REPL is pretty short-sighted.
Rust succeeded in pushing back the Overton window of programming languages because it didn't try to innovate in places that didn't matter. A more radical language might be more aesthetically appealing to someone like you but won't change the experiences of any significant number of developers in their day to day work the way Rust has.
Rust moving away from its more ML-leaning beginnings is a downside, to me at least.