The OpenACS web server toolkit has a lot of useful Tcl utilities, including the ad_proc procedure, which wraps proc and allows adding of switches, inline docs, and more.
I think it would be very useful to turn ad_proc into a built-in command and incorporate it into TCL.
I implemented something very similar a while ago, it's indeed too bad it's not built-in. I don't think you need such a "quasiquote" function, [list {*}$args] can escape a single command, and then it's a matter of joining multiple commands using a newline. IIRC that's how I did it.
I also had further fun with wrapping "proc" by implementing a "pyproc" which called out to Python while looking like a normal Tcl proc.
Tcl is the shell done right. Simple, logical, consistent.
Synopsys tools (either CosmosScope or Custom Wave view) do it by the way of names following values. Like:
measureFoo $signal threshold 0.9 edge last
As a search of the Tcl wiki shows, attempts to add named-argument capability to the Tcl proc command have been around for several years.
My own nxproc extension is more comprehensive. (See wiki [0].)
The extension enables named arguments, regular positional arguments, and 'rest' arguments, nxargs and nxunknown. Nxproc also provides (optional) type-checking of procedure arguments. (Types: string, number, bool and enumerated. Enums are lists of values restricting what the arg can contain.)
Nxproc supports TclOO with nxcontructor and nxmethod commands -- same feature set as "plain" nxproc. Also provides case-insensitive '-ci' variants, and runtime display of named-argument default/actual values and types.
Nxproc is a Tcl C extension. Bundle has Windows, Linux binaries. Compiles easily on other platforms.
[0] https://wiki.tcl-lang.org/page/nxproc