This is a great response. I'm curious why something like this wasn't posted within 24 hours of RapGenius going public? I'd bet that a more thorough, technical reply would have mitigated a lot of the PR issues.
Also, we wanted to respond to our customers first and foremost, and general community discussion second. So we spent close to a month on skype/hangout/phone with hundreds of customers understanding how and at what magnitude this affected their apps.
That was hugely time-consuming, but it gave us the confidence to speak about this in a manner that would be focused on customer needs instead of purely answering community speculation and theoretical discussions.
The rest of the whole thing was people who were unsatisfied by the change and wanted the old product offering to return and/or felt shortchanged by Heroku. Luckily, Heroku doesn't lock you into their platform like GAE does, for example; it's essentially a bunch of shell scripts to deploy binaries on EC2 workers, a hosted instance of Postgres on EC2, some routing and ops as a service. Anyone who wasn't happy about the change could've contacted Heroku to say "you said we would be sold non-random routing, but you've sold us random routing" or moved their app away to another provider or even their own servers.
Does this suck if you wanted the old service? Sure. Witness the flak that the canning of Google Reader got and it's obvious that discontinuing old services isn't exactly a popular decision. On the other hand, you can self-host (it's massively cheaper than Heroku) or switch to another provider. And if there are no other providers that specialize in Rails hosting, isn't that a business opportunity?
That's not to say I wouldn't send it to a lawyer. But I'd do it with some hustle. Something like: "This is going out in 24 hours. Please comment ASAP!"