I also think full concurrency/access from all Workers is the improper implementation. The most important focus when writing commonly-labeled "HTML5" apps shoul

I also think full concurrency/access from all Workers is the improper implementation. The most important focus when writing commonly-labeled "HTML5" apps should be performance, for now at least. We are, at long last, overcoming the click-fetch-wait style of interaction with Web data; the dynamic nature of its replacement is a key feature, and the influx of performance-constrained rich-web devices need to support complex dynamic apps too. So, I think we need to rethink the roles of common Web technologies. The DOM is no place for state; it should be treated more as an interface layer than a representation of data. JavaScript engines are tuned enough, and the basic architecture for extremely rich apps is in place, we just need to use our tools intelligently as implementors.