TBH I think the reality is that there just is not a good wxdata cloud platform out there that really ticks all the boxes.
There's an opportunity for someone to develop one but it would need to be done on a full commercial basis, probably involving 2-3 developers plus an admin role - the requirements for continuing development and ongoing maintenance & support are just too much for one person to handle, no matter how skilled/dedicated.
So there would probably need to be an annual sub (or more likely some sort of fremium model with tiers of capability from free to high-end). If you could design a site good enough to sign up (ultimately) say 2000 users worldwide at an average $50-100pa then the economics would start to make sense. The site would need to be good enough to justify that subscription level. I honestly don't know whether this level of demand exists, but I suspect that it might, especially if you could also attract 'business' users like farmers with a real need to have comprehensive and up-to-date presentations of weather data.