I initially posted this into questions forum, but I've been suggested to move it into ideas, so here I am…
How about making a Kustom android API so developers can build Kustom Weather Plugin apks with their favourite weather provider?
Something like:
"update now" kustom-intent: retrieves the weather data for a given location.
"get X" kustom-intent: parses and returns the data (X) from the last retrieved data set for a given location
Of course, it's always more complex, but it's just an initial idea. Any other architecture (as the one already in use in Kustom Weather Plugin) will be OK.
Regards.