Indeed a good case study! :)
Got to learn few things, and thank you for that!
I would like to provide a couple of inputs here, in order to enhance the user experience (from my perspective)
1. Showing the payment method that is already set for the recurring payment:
In the subscription details, if I get to see which of my credit card will be used for the recurring payment and an option to change the same. (I understand that proper API support will be required for that)
2. Grouping of subscriptions based on the genre:
Most of the times, I can have many subscriptions ranging from learning, entertainment, grocery shopping and so on. So if I get to see the subscriptions in separate groups, it would be easier to manage them! :)