Lessons for the Elemental Invasion that We Should Have Learned from the Undead Invasion

Panic on the streets of Stormwind, Panic on the streets of Ironforge.
And I wonder to myself, will anything be sane again?

The Elements of Azeroth are getting frisky! Doomsday cults are running through the cities! Dogs and cats lying together! Mass hysteria! This can only mean one thing: It's time for the world event! Woo Woo!

I can't think about all this starting up without thinking about the last time it happened: two years ago, when the Lich King pulled his "Plague-the-Grain-and-Turn-Everybody-to-Zombies" routine. And for a few days it was utterly super-fun madness with two scoops of awesome on top.

But, the event wasn't entirely smooth and a lot of this was due to player reaction to the events, a few small glitches with the implementation, and some clashes between how players were "playing" with the event.

I know I learned a few thing from that, and I'm pretty sure Blizzard did too. So, following are some lessons learned from the Zombie Invasion that will probably help us weather the Elemental Invasion.