I had the opportunity to completely reskin the Vigor bar for the Algarian Stormrider mount, which is included in The War Within Heroic Edition.
This mount has 4 different armor colors you can select from in the Rostrum of Transformation, and we created 4 color variants of the bar that reflect the player's armor choice for the mount. This was the first time we've made the UI reflect the player's customization for their mount.