Absolutely - but the fact that all the healing we're talking about comes with a cost of a full action is something that also needs to be factored into the equation. An Apothecary with Bottled Courage and Potent Remedies can heal an average of 6 per turn and get off three attacks; he may not be the BEST healer but that certainly makes him a fantastically efficient one.
Definitely worth considering. As long as the bard has the lute, cacaphony (activating understudy) only "costs" 2, as he can always recover 1 of the 3 suffered by using the lute on another hero. And since cacaphony grants +1 stamina, he really only needs to rest every other round.
The Bard certainly isn't the only player in town when it comes to healing- but his combination of good healing, good fatigue regeneration, and the ability to do it without the use of actions (for the most part) makes him stand out.