I don't use gnome shell and haven't noticed any discussion.
I would lean to publishing your data via MQTT to a local broker, and
then adding to gnome shell the ability to get weather data from MQTT.
That would let people reasonably easily connect various things, not just
weewx, and wouldn't require changing weewx or writing weewx-specific
code in gnome shell.
The weewx mqtt extension has been working solidly for me. I publish
data in json at every (5m) archive interval, and read that into Home
Assistant.
I suspect I am more on the pro-MQTT side than many, though. For me it
solves enough problems that the cost of setting it up (which isn't that
high) is worth it over all the things I am doing with it.