The "hard" work of creating the Workers technology and service is useless if they don't do the arguably easier (but more tedious) work of getting the ecosystem to play well with Workers. This means making a list of the Top 1000 most popular packages on Node.js, and finding ways to make as many of them work on Workers as possible. For the ones where it's too hard/impossible, there should be *well-documented* alternatives.
JSR also does a good job of indicating what packages work where—if it gains traction.
Also, one thing that isn’t made clear in the documentation is that you cannot test in any real sense. They have buggy, toy PoC testing but there’s no way to do local testing for real world apps.
If you’re making anything more complicated than a blog it gets very painful very quickly.