No, because heartbeat added a major value to every user of WP (to whit - it auto saves posts better, just for one minor example). And I didn't say 'bulk editing' wasn't used often.
Let's go back. The ORIGINAL wish "I sometimes want to deselect categories when bulk editing."
I take this to mean "Sometimes I want to say 'Remove this category from all the selected posts.'"
Since its introduction [Bulk] Edit only adds tags and categories. There were talks about implementing removal too but that was never a high priority. There are some UX questions too: shall we add extra boxes with the existing cats, tags, etc. (that may be more confusing) or shall we add a red checkbox above the existing cats saying "Remove checked categories from the selected posts". Or perhaps radio buttons Add (default) / Remove.
(note that the ticket eventually shifts to issues with QuickEdit killing things).
We hit UI walls with it last time, making it so that expected behavior was understandable. Will this be revisited in the future? Probably. Nearly everything is, over time, but to say "This should start as a plugin and see if it gains traction" is not a BAD thing. 90% of new features in 3.7 and 3.8 are starting as plugins.