Fair point, and agree that the current Wordpress UI could be improved.
I’d argue the main source of confusion with the current WP “Publish” panel is that the three primary actions (Save Draft, Preview, Publish) are rendered in three (ugh!) different locations (top-left, top-right, and bottom-right, respectively) which hinders scanning and increases the likelihood of users not
Personally I’d group these buttons together in the panel’s bottom row/section with the Publish button still rendered as the primary action in Blue, but with a confirmation dialog on clicking (“This will Publish this article to your live site — are you sure you wish to continue?”). The confirmation dialog could easily be turned on/off under WP user preferences for more confident/experienced editors.