To clarify: I understand that getting another dyno would solve this problem. I love heroku but I think that they need to rethink the idle process. Some users only need 1 dyno and a bunch of addons. If we are paying decent money then the idle threshold should be increased, in my opinion.
It's just semantics. They are giving away the first dyno. Would you prefer they took that away when you purchased one for real? 2 for the price of 1 seems pretty nice.
That and fundamentally (as you noted about being optimistic) you're paying $100+ a month for an app that gets zero traffic. That seems to be the core issue.