I'm obviously a bit biased here, as the architect of Cloudflare Workers. But, I think it's a much better fit for Sandstorm than containers were. Sandstorm suffered from some really bad cold start times, especially with every "grain" (e.g. document) running in its own container. It also led to a lot of other inefficiencies.
The down side of this is of course that it'd be much harder to port existing apps to the platform (unless maybe if they were already written to target Workers). But I think:
* Sandstorm didn't support existing apps very well anyway. It took a lot of work to convert apps for Sandstorm's security model. Many of the best Sandstorm apps were written from scratch for Sandstorm -- which incidentally was a lot easier than writing a traditional app, because Sandstorm took care of a lot of the work for you.
* AI-assisted coding takes a lot of the pressure off to support existing apps, because it'll be that much easier to build new ones. A Sandstorm-like environment would be a great fit for vibe coding since it takes care of so much of the boilerplate and enforces security in a way that the app can't screw it up.
What do you think? Would this ruin it for you?