Just like the other classes the Druid received several new spells with Wrath of the Lich King, improving their arsenal in several important spots. There is, for example, the "Savage Roar", a finishing move for the Cat Druid. This finisher increases the Cat's attackpower by 40% for up to 34 seconds. This greatly increases the melee damage, provided the Druid has enough time to collect the necessary combo points.
A Tree Druid got the Nourish spell, a fast and efficient helaing spell and something that was missing from the Druid's toolbox for some time. Nourish receives a 20% bonus to its effect as long as a heal over time effect is active on the target., which should almost always be the case when a Druid is healing.
Lots of new spells were added through talents. Moonkin Druids received two area of effect spells with Typhoon even able to knock back enemy targets. Starfall is a unique and special spell as it is a fire and forget mobile spell that moves with the caster.
Feral Combat Druids are now able to enter a Berserk mode, gaining immunity to fear effects and greatly increasing their damage. Survival Instincts allows them to gain a short health boost, which is similar to a Warrior's Last Stand effect. Tree Druids gain the Wild Growth spell, a group- or area of effect heal very similar to the Priest's Circle of Healing.