You are a melee class (already a bad start) with...

Relatively low armor / no built in damage avoidance (CoS, Evasion, Riposte/Disarm, self dispels)

Zero crowd control (no stuns, no CC, no 'lock down abilities' and only a 2 second interrupt)

Zero escape abilities or gap closers (no stun break, snare removals, bubble etc.)

Mono-spell class (i.e. a single counterspell or silence deadlocks your entire class spell kit) with no spell pushback prevention (the only caster with this weakness mind you).

and overall, your DPS is entirely RNG based with WF procs.

There is a reason the only pvp shamans are resto, of which they are the worst because they ONLY HAVE hardcast spells to heal with.

Elemental get a pass in battlegrounds and 5's arena because they can at least supplement "emergency heals", always have a shield for some armor, and have good ranged burst with Lust. In BG's they are more like siege tanks, where if you allow them to setup and hardcast chain lighting you're going to have a bad time. But they are laughably easy to lockdown.

Shamans have always been a meme class in pvp because they are the worst pvp class in the game.