Stating the obvious wrote: He should never have started. His new doctrines have had a baneful effect on his followers.
This pagan world has rocked Reformation scholarship to its core. Pandemic gluttony, fornication, homosexuality, pornography, adultery, divorce and remarriage have so bludgeoned Reformation theology as to render its chief tenants inert.
At least Piper is honest enough to try to publicly grapple with Reformation issues including "Christian" divorce and faith alone which, like yesterday's news, is worthless and insecure. Inquire of Luther's right-hand man about this.
May Piper's successor also have the fortitude to desire God with his whole heart, mind, soul and strength.
Truth is more important than blind adherence to a mere reformation.