Thanks! Your solution would be ideal for most people.
Unfortunately, remove_action isn’t available to me, because I’m using Tom McFarlin’s WordPress Plugin Boilerplate. (add_action/filter become methods, no equivalent for remove). Adding a remove_action has been discussed for several years but not implemented.
This fork of WPPB adds a remove method.
However in the end, I implemented a separate filter just for post title, on wp_insert_post_data, which sets a value for $data['post_title'].
