To further extend the airline analogy, it's as if you had bought one of these "fast travel" products and were told to buy more plane tickets to avoid delays!
The tort (aka crime) committed is the deceitful way in which nature of the product was marketed to the clear financial benefit of Heroku and to the clear financial detriment of the customer. The fix offered to customers is always an up-sell effort to "buy more Heroku products."
The thing about Heroku's intelligent queing system is that it lowers customers' costs and thus Heroku's profits. Switching away from intelligent queuing to random queuing was a business decision with clear moneymaking advantages for Heroku.
In one fell swoop, the move made the value of a customer to Heroku skyrocket, potentially increasing its valuation upon acquisition and/or helping the founders more easily hit any earn-out revenue targets required by Salesforce as part of their acquisition.
And, in this case, documentation regarding the way their system works, as well other of their materials was overtly untrue. Beyond that, customers would merely need to show damages and also that Heroku profited from its untrue statements.
Whether it intended to mislead or not, Heroku could have a real problem on its hands.