Enhancement Shaman is good, but it has a few distinct weaknesses. First and foremost, they don't really have a composition that they fit that well into. The current meta revolves around raid buffs, which Shaman has
Windfury Totem, but it isnt as popular (or strong) as other raid buff options. Enhance's tier is really strong. It buffs the AOE, funnel, and burst damage profiles of the Enhance Shaman and really makes their damage sneaky good. When coupled with
Ancestral Guidance, the shortest kick in
Wind Shear,
Capacitor Totem, and
Thundershock knockup, it's a C-Tier choice. If there was a better comp for Enhance it could easily be B-Tier, but without one it's hard to move up.
Enhancement’s big drawback is survivability.
Astral Shift is a very strong cooldown, but on fights that have one shot capabilities whenever Shift would be on CD, then Enhance is very vulnerable. You do have access to
Spirit Wolf, but going Wolf before a big hit feels awful.
Brimming with Life is also good HP wise. Overall though, if you pull around an Enhancement Shaman's priority damage they can do some nasty things.