Subjectively, I see no point in having "val", "var", "let", "def", "fn" symbols which bring only noise to code. Why would you want to explicitly tell that something is a value while all you need to do is write its type and name?

double[] arr;

bam! Simple and clear.

What about functions? It has input, name and output and D nicely presents you with

double[] createArray(int size) {...}

This is as little typing as you can get while keeping readability.

And here is a basic Rust function

fn add_one(x: i32) -> i32 {...}

What kind of type is i32 btw? oh, there is u32 as well. integer 32bit and unsigned 32bit? What on earth are these? Ah, this is just D's size_t, the same size_t as in C/C++. So that C/C++ ppl have zero overhead reading D code and for Rust they will google. To top that, you have also -> because of the type after the definition scheme. Needless verbosity, same thing in Scala.

What about Rust unable to drop parenthesis after a function?

self.host_addr.clone()

Should I mention Rust's UFCS?

But I am nitpicking, right. This doesn't make a language bad in any way. However, as I said, Rust readability is pretty subpar in addition to already steep language learning curve.