> So to answer your question, there was never some crazy-awesome implementation of a distributed global queue that we got rid of.
This sentence is really good, and I would humbly suggest you consider hammering it home even more than you have.
I gathered early on that there were inherent scaling issues with the initial router (which makes sense intuitively if you think about Heroku's architecture for more than 10 seconds), but I feel like most of the articles I've seen the past few weeks have this "Heroku took away our shiny toys because they could!" vibe. (Alternative ending: "Heroku took away our shiny toys to expand their market to nodeJS!")