I look at the Tribal Shaman costumes, and I look at how the enemy Shamans work, as well as some Shamans in other games, and I just had to think... What if ESO had Shamans and what would differ them from Templars? Oh! How about a class based around buffs and tribal magic?
Note: This isn't completely thought out. It's an opinion, not a full on idea.
Shaman-Shamans help their allies with totems and prayers to support and buff themselves and others, or debuff their foes.
Tree 1-Prayers of Death-This tree is based around using magical items to call death upon your foes.
Tree 2-Totems of Life-This tree puts out different totems to boost certain stats for team mates who are inside the radius. The totems can be destroyed by enemies in PvP, and do not gain aggro in PvE. Totem bonuses can include increase defense, boost health, magicka, and/or stam regen, or even cause enemies to miss you (Totem of Mist?).
Tree 3-Blessings of War- This tree is meant to debuff the enemy. Call upon nature to aid you by raising vines from the ground and binding those in the radius of this AoE ability. Lower their defense by speaking the language of your ancestors. I don't know, just debuffs.
Build on this if you want. I don't care if they do add a Shaman class (they probably won't add any new classes, since the classes we have now are already very diverse). It would be neat to see, however.
Argonians always and forever.