The word Moonkin and OP really doesn't fit for most people in a PvP setting. This is more than understandable. As you reach level 80, its a whole new world when it comes to Player Vs Player Combat. You have the gear level difference which can be from a fresh 80 in quest greens to someone in full t9.5. Not to mention all the armor reducing abilities melee have which makes moonkin's armor worthless and allows a melee to destroy us in a few seconds.
However, while playing my Lowbie-Kin, Foofe, I discovered the fun of PvPing once again as a moonkin. With her only level 40, its easy to take on melee as well as casters. No one is maxed out and has every spell possible to take you on, but still are able to give you a good competition. So, while really getting into the PvP scene again as a moonkin, I found sheer enjoyment of being able to root a Rogue and having them stuck there the entire duration. As well as the fact as if they got on me, I could live through a stun and get away, and outheal their damage with a Rej and Regrowth.
Now, fighting twinks is another story, they are meant to destroy you, so I refuse to turn off my XP gain since I do wish to level her (slowly, but surely). But as I stated, PvPing as a lowbie-kin is just great. It really evens the field when melee don't stack their ArP, or have Cloak of Shadows or even Bladestorm.
What makes Lowbie-Kins OP in the Lower Brackets?
With Moonkin form, we have a high amount of armor. Of course as we go higher and get into the 60's alot more abilities will effect our armor when a melee gets ontop of us. But currently, with no ArP stacking peeps in the 40's, its heaven and you actually last more than 5 seconds. We also have players who aren't maxed out on damage, so we can actually hot and run once more. Its kinda like Vanilla WoW once again, where druids would just hot and run, only, now we can do damage.
Our roots are the most powerful thing ever in low level brackets. Even if you don't have Moonkin form yet, its still great to have. Before I picked up Moonkin form, I was still a force to be reckoned with in BG's. I even had an enchance shaman pop after I killed him, and I just killed him again. He tried to kill me since I only had 10% health, but my rej kept me alive the entire time.
Insect Swarm and Moonfire are a great combo. Just using these and keeping yourself up is so easy and the outcome is funny when a rogue dies to it. Them not having cloak of Shadows is like a dream come true. Going against a caster is about the same as it is at 80. Hit or miss. Its all about the player behind that caster and how they react and how things go.
Either way, I love PvPing again (And no, typhoon'ing people off Thunderbluff doesn't count as Moonkin PvP) but only in the low level brackets. So I suggest if you have an alt druid to try respecing them Moonkin and trying it out. You may find that you enjoy it.