To my point of view, the routing is "random" thus kind of unpredictable. If scaling becomes more of an issue with my business, the last thing I want is to have random scaling issues that I can not do anything about because the load balancer is queuing requests randomly to my dynos.
I want my business to be predictable and if I'm not able to have it I'm going to pack my stuff and move somewhere else.
For now, I'm happy with you except for your damn customer service. They take way too long to answer our questions!
Can you email me (adam at heroku dot com) some links to your past support tickets? I'd like to investigate.
Thanks for running your app with us. Naturally, I expect you to move elsewhere if we can't provide you the service you need. That's the beauty of contract-free SaaS and writing your app with open standards: we have to do a good job serving you, or you'll leave. I wouldn't want it any other way.