Good question! Thankyou for asking, that is something I have thought about, being a worgen main.
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War paint - Bloodfang worgen ingame use war paint in the Hillsbrad Foothills, and in the Alliance garrison.
https://wow.zamimg.com/uploads/screenshots/normal/870522-bloodfang-forsaken-hunter.jpg
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Body Scars - Alpha Prime and several other worgen in the comics have lived a very savage life, and are covered with scars from their adventures. They added one scarred face option recently, and I love it.
https://gamepedia.cursecdn.com/wowpedia/thumb/e/ea/Alphaprime.png/300px-Alphaprime.png?version=3856c28495f804a98f6253a6fabffa68
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Bite marks - Again referring to Skyrim, and world of warcraft worgen, the curse is spread through bite. Bites are deep, and often leave scars.
https://vignette.wikia.nocookie.net/moon-guard/images/9/99/Halfordcursed5.png/revision/latest/scale-to-width-down/340?cb=20150514211111
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Wolfish features in human form - In the comics, some characters bear slightly more bestial features when they are slightly enrage, but not quite to the point of shapeshifting entirely. Genn Greymane in Heroes of the Storm as an example. Slightly more pointed teeth, glowing eyes in human form, extra body hair options, etc.
https://i.ytimg.com/vi/qWfFE-_6f1Y/maxresdefault.jpg
Now, if I wanted to be far more ambitious, I would suggest the long-sought for kaldorei form as well, because both kaldorei and humans can become worgen. That, and customizing your human form and your worgen form separately. All these customization options have been depicted in the game and lore.