Ever since the Warden Bear got a preorder cosmetic option some people have been wanting some cosmetic options for their other combat pets. I know buying a single option for a single class probably wouldn't sell as well as mounts, costumes, and hats but the market for them is still there since we already see players buying things locked to a single race like Khajiit and Argonian cosmetics.
After seeing the new Meet the Character article for Lady Thorn I realized she had a very unique vampire lord armor style. For those who have not seen it here it is in the spoiler tag.
While I know some people would love to have the wings on their Blood Scion transformation, it'd be cool if there were different armor types, and maybe even hairstyles, we could get a hold of to equip onto our Blood Scions to make them look more unique to us. Apply the same reasoning to Werewolves with different fur colors and body types, as well as different looks for the Bone Colossus transformation and ZOS could open up a new market in ESO.
PC NA - Ceyanna Ashton - Breton Vampire MagDK