I'm sure there was massive abuse. All you needed was a script that regularly pings (well HTTP request) your dyno and it would never suspend. The next best alternative would have been free trial period. I have a friend who does Wordpress hosting and the stories I hear about their abuse cases on the free tier are scary.
Heroku's free dynos still serve their purpose and are good enough for prototyping, testing and (during office hours) staging.
In my opinion it was the right decision.
(Charging $20/month for hosting an existing SSL certificate is too expensive though. https://addons.heroku.com/ssl)
$7 is pretty good value for what they offer. Happy to pay it.
Huginn can no longer be hosted on Heroku, which is making it harder for new users to try it out.
The cheapest Digital Ocean instance is 5$/month but then you don't have all the goodies like plugins and auto-deploys.
I'd be more than happy to pay Heroku if I had any public facing apps that required more uptime, but for those simple personal apps I don't require it.