Kill Visage forms entirely, just let Dracthyr transform into all of the mortal races, and spend that saved time on creating more customizations for the Dragon form, the thing that I'm assuming most people are actually interested in. Then, during x.x.5 patches, add in fun side content of varying difficulties that allows you to unlock a few different kinds of horns/draconic customizations for your chosen mortal form.
I accept checks Blizzard.