I'd like to suggest changing XenForo_Model_Tag::adjustContentTags() to not insert into the database directly and instead use the data writer for the tag_content table. Alternatively, just calling $this->_insertTagContentRecord() or something would work as well. Basically I want to do some stuff when tags are inserted to the table and deleted from the table and right now it's not a very friendly process. It's not a terrible process since all the tags getting added and removed are available but it still requires looping through the array(s) a second time. During the beta process seems like a reasonable time to suggest this and possibly make this minor code change.