PEP 614 has recently completed a round of review on Python-Ideas:
https://www.python.org/dev/peps/pep-0614/
It proposes that the current decorator syntax restrictions be relaxed to allow any valid expression. Nobody has raised any objections, but I wanted to gather more feedback here prior to bringing it before the Steering Council.
I couldn't point you to a specific thread reference, but I think we came to consensus years ago that this was a good idea that was just in need of someone with the time and inclination to do the work :)
Thank you!
Cheers,
Nick.