pretty much; "jack of all trades, master of none" actually fits pretty well.
Sure, they may have super dps spells. But they don't have blink and frost shield.
Sure, they may have windfury procs, but they don't have plate armor or execute.
Sure, they may have travel form, but they don't have rooting spells.
Sure, they may have self-rez, but they don't have soulstones or fear spells.
and above all...sure, they have self heals, but they don't have divine shield!!
And one huuuuuge handicap: Shamans have no stun ability. Their only spell interrupt is earthshock, and its basically a gimp counterspell with a bit of damage to it.