A patch has already been written for rust-clap-derive-3:
<https://issues.guix.gnu.org/56037>.  That patch series also adds rust-
clap-lex, so some inheritance may be in order.

On rust-windows-... crates: these crates are unnecessary in Guix.
If a package complains about not finding the dependencies, you can just
remove the dependency declaration from the Cargo.toml

Likewise, #56037 already updates rust-textwrap.

Also, rust-adler is already in Guix, so you can use inheritance there.

Why is there a separate rust-autocfg-1.1, instead of updating
rust-autocfg@1.0 to rust-autocfg@1.1?

In rust-object: why change the inheritance?

In rust-once-cell-1: Why remove the skip-build?  Also, you removed some
dependencies (rust-crossbeam-utils, rust-lazy-static and rust-regex),
but they are still used, according to
<https://github.com/matklad/once_cell/blob/v1.12.0/Cargo.toml>.

Also, if you're willing to wait a bit or help out, I've been working on
simplifying the Rust packaging system in
<https://notabug.org/maximed/cargoless-rust-experiments/>.

(TBC: only some quick comments, didn't look in any detail)

> +     `(#:tests? #f ; missing files

Then you can add the missing files.

> +    (synopsis
> +     "Tool to conveniently learn about the disk usage of
> directories, fast!")
> +    (description
> +     "This package provides a tool to conveniently learn about the
> disk usage of
> +directories, fast!")

Is markety, and the synopsis and description just contain the same
information.  See (guix)Synopses and Descriptions.

Greetings,
Maxime.