Pros.
Druids pair with a priest or pally are great for initial heals after an intense damage spike by utilizing hots.
Wild Growth, great for when there is a decent amount of melee dps taking damage, use it on the tank and you generally heal the majority of the other melee.
Great instant cast heal with Swiftmend, especially when glyphed. It won't consume a rejuv or regrowth.
Rebirth, you're in combat res.
Revive, out of combat res, not on a timer.
Nourish, acts like Flash of Light so to speak in cast time, does 20% more healing if a HoT is on the targetted character.
Tranquility, still the best party heal you can offer.
Innervate, with a high amount of spirit, and glyphed you can offer someone else the innervate and still get enough mana back to finish a fight.
Tree of Life Form, increase in healing and armor for the druid healer.
Removal of Poisons and Curses.
Nature's Swiftness, makes the next nature spell instant cast, which generally is used with Healing Touch, to kick out a large spike mitigation heal.
You can CC as the healer using Entangling Roots.
Imp Mark of the Wild, 1050 armor, 51 to all stats and 75 resist, add on 40% to armor and stats if talented.
I seriously could just keep going on why a druid healer is amazing. They're versatile and you're given so many heals and options to choose from its pretty much like cheating.
Otherwise I seriously suggest checking out both the shaman and druid healing guides available on allakhazam those will also help you make your decision.
Oh and I almost forgot... As a druid... You can heal.... DPS.... and tank. :D