Monthly automatic renewal is a convenience for your subscribers. Annual automatic renewal probably isn't. It can obviously create ill will and doesn't give you as much flexibility to increase subscription rates.

Opt-in for long term subscriptions would appear to be more subscriber friendly and avoid some of the issues mentioned. Offering multi-year subscriptions could provide even more cash upfront without the brand risks associated with automatic annual billing.

Opt-in communications would likely be no more resource intensive than implementing email notices about an automatic annual charge. My gut tells me that, "We hate losing you as a customer" may build more goodwill than "it's in the fine print."

Based on your post, customer service resources are being diverted to former customer service. And there's no money in that. Good luck.