I think it would be cool if a new layer of cosmetic options could be implemented. Maybe not only for cosmetic options but for stats and grind purposes. It could act like an maj/min adornment slot. Something like trinkets could be added for grinding/farming. And also add stats.
Some examples would be like skull trophies added to the armor, drinking horns, barrage of arrows in the upper back/shoulder. Even if they don't add stats (it might even be better if kept strictly cosmetic) it would be cool to adorn our toons in some extremely rare findable items. Mayne even allow for multiple items to be equipped at once. But also that being key make them extremely rare if only cosmetic. But also allow then to be sold as opposed to bound.