Not at all, they can deal quite a lot of damage, and sometimes in the hands of a skilled player they can create a large amount of disarray between the enemy team.
Balance just has a higher skill floor than most other specializations, so most people tend to avoid them.
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Healing Tide Totem is the only issue that Elemental has as far as 'strong off-healing' goes. Other than that, they're fine. Healing Surge has to be cast for a hefty amount of mana, so it's hard to use while you're being trained. Ancestral Guidance has the same effect, you have to be casting for it to be effective.