Ever since shamans were given to both factions in BC, shamans are compared more to druids than their old paladin nemesis. Unlike the paladin and druid, however, shamans were never given a tank spec. This, along with the fact that Enhancement at one point had several legitimate defense talents in its tree, has led to a decade-long discussion in the community over a potential 4th spec for shamans or a revamp of Enhancement into a tank spec such as Geomancer or Earthwarden.
Personally, I do not like when Blizzard takes a play style away, and so I am in favor of the fourth spec so that shamans can still be melee fighters, however there will be thematic consequences for the Enhancement tree. The Resto shaman heals with water, the Earthwarden tanks with earth, and the Elementalist roasts his enemies with fire and storm. Enhancement has always had heavy wind themes, but I feel like this steps on the Windwalker monks way to much and this would be a missed opportunity to bring a Runemaster spec into the game.
Runemasters are classified as mystics. They are essentially shamans but without totems who use runes instead, and these runes give them mastery over the elements. They have an arcane twang to them, tattooing themselves with magical runes, and their history is deeply rooted in tauren and dwarf heritage. As in tauren and dwarf shamans are probably more Runemaster than shaman. This is the perfect theme to revamp Enhancement into if a fourth tank spec is ever created. It’s new, it’s unique, it’s something the community has been asking for for a long time.