It seems that a lot of people are ignorant to what a Moonkin brings to the raid. I will honestly say that 90% of the players only see a Moonkin as a +5% spell crit buff for casters but there is more to us than that.
+3% hit to the entire raid - A Moonkin specced in to Improved Faerie Fire brings a valuable utility to the raid with 3% hit. Not just melee, not just spell hit. As long as the Moonkin's Faerie Fire is on the mob the entire raid gets this buff.
2% avoidance for tanks - Insect Swarm is a DoT but also reduces the mobs chance to hit by 2%. Yes, it even works on raid bosses.
25% reduction of attack speed - Hurricane is an unappreciated AoE that is usually lol'ed at for it's lack of damage. What people DON'T know is that ANY mobs affected by Hurricane has their attack speed reduced by 25%. Sure, all Druids get Hurricane but a tank or healer isn't going to be using this very much.
More aggro on the tank - Brambles increases the effectiveness on Thorns which in turn increases threat generated by the tank while taking damage.
An additional Innervate - Moonkin provide good single-target DPS while also bringing the utility of an additional Innervate for the healers. This is a risk free Innervate because the Tank sure isn't popping out of form to use his/hers and the Resto Droods don't have to stop healing to use theirs.
An additional Rebirth - The same benefit as listed above for Innervate. The healers don't have to stop to use theirs and it adds another one to the pot. Good times!
Backup Healing - Balance Druids get talents that increase their spell damage and healing by a certain percentage of their Intellect and pack a lot of it. In situations where tanks need that extra healing, a Boomkin can pop out of form and throw up every HoT a Resto Druid has, albeit less effective.
Treants - Ok so this is just a fun spell to use and it never fails to hear someone on vent say "WTF?". Sure it brings nothing to the table but I don't leave home without them. Sometimes wiping repeatedly brings everybody down but Treants turn that frown upside down. I'm a rapper. Quote that.