Cargo is not really good. The very much non-zero frequency of something with cargo not working for opaque reasons and then suddenly working again after "cargo clean", the "no, I invoke your binaries"-mentality (try running a benchmark without either ^C'ing out of bench to copy the binary name or parsing some internal JSON metadata) because "cargo build" is the only build system in the world which will never tell you what it built, the whole mess with features, default-features, no-default-features, of course bindgen/sys dependency conflicts, "I'll just use the wrong -L libpath for the bin crate but if I'm building tests I remember the ...64". cargo randomly deciding that it now has to rebuild everything or 50% of everything for reasons which are never to be known, builds being not reproducible, cargo just never cleaning garbage up and so on.

rustdoc has only slightly changed since the 2010s, it's still very hard to figure out generic/trait-oriented APIs, and it still only does API documentation in mostly the same basic 1:1 "list of items" style. Most projects end up with two totally disjointed sets of documentation, usually one somewhere on github pages and the rustdoc.

Rust is overall good language, don't get me wrong. But it and the ecosystem also has a ton of issues (and that's without even mentioning async), and most of these have been sticking around since basically 1.0.

(However, the rules around initialization are just stupid and unsafe is no good. Rust also tends to favor a very allocation-heavy style of writing code, because avoiding allocations tends to be possible but often annoying and difficult in unique-to-rust ways. For somewhat related reasons, trivial things are at times really hard in Rust for no discernible reason. As a concrete, simplistic but also real-world example, Vec::push is an incredibly pessimistic method, but if you want to get around it, you either have to initialize the whole Vec, which is a complete waste of cycles, or you yolo it with reserve+set_len, which is invalid Rust because you didn't properly use MaybeUninit for locations which are only ever written.)