First, before reading the first paragraph of the post which explains where the word comes from, I was able to get a general idea of what the word was supposed to mean. I looked into where the word came from, and it seems to have started appearing in a few sources, including:
There's even a GitHub organisation and repo with this name too.
The thing is, to me (and I guess I should declare myself a pedant and proud of it) this neologism is ugly and not really thought through, for these reasons:
It's a hybrid of Greek (poly) and Latin (nimbus). There are of course other words that are hybrid, but if we're going to create new compound words, surely we want to avoid hybrids? After all, the original meaning of the word "hybrid" has rather negative connotations.
If we're going to go for tacking a Latin word onto the end of a Greek one, let's at least make sure it's the right Latin word. "Nimbus" doesn't mean simply "cloud" in Latin, it means "dark cloud", like a thunder or storm cloud. Perhaps not exactly the meaning we want to convey when talking about something positive.
The word seems to be employed mostly as an adjective right now. Using the raw nominative singular form of the noun "nimbus" is hardly appropriate, then. At least change the ending to a more traditionally adjectival suffix "-ic", in other words "polynimbic".
I can't see this word without my face contorting into a grimace, especially when it would have been easy to come up with something a lot less unpleasant.
My suggestion? Polynephic. Nephic from the Greek for cloud: νέφος.
Thanks for your attention :-)