How feasible would it be to have webservers compile javascript and serve it to the browser already preprocessed (as far as possible)? The same URL could be used, but a different mime type acceptance signaled by the browser using the Accepts header. The webservers, instead of returning text/javascript would return application/javascript+moz22.
Then, most of this race towards hotspot optimization would be less important.
I do not trust 99 servers out of 100 including not only those I intend to communicate with but others sitting in the middle of my connection, to deliver the same binary my browser would render in a few milliseconds.
The web is a wild place, let's not increase our attack surface.
Then, most of this race towards hotspot optimization would be less important.