I love the idea of Workers! The catch I ran into last year was the 1MB limit for webpacked JS files. That puts many npm packages off limits -- I ended up doing some webpack magic to stub out subdependencies I didn't need from a package that didn't support tree shaking, which is pretty far from "just works."

Here's a good thread where the problem package was a SOAP library depending on "request," but the same logic is easy to run into with any app: https://community.cloudflare.com/t/worker-size-limit-a-probl...

The upshot is if you have an idea that would be easy with dependencies, you can't reason about how difficult/possible it will be with Workers until you spend some time figuring out if the dependencies can be compressed small enough to use -- and the answer may change partway through if you need to add something.