World Events

Instead of just having world events that relate to an expansion, or patch, have weekly or biweekly world events.  They could be attacks on central cities, or attacks on small towns in places, by NPCs.  For example; Centaur could try to invade Thunderbluff; Demons could pour out of Ragefire chasm into Ogrimmar; pirates, murlocks, or naga could attack the Darkspear Islands; the Scourge, or Scarlet Crusade could attack Undercity; trolls could march on Silvermoon City; Leper gnomes and Troggs could attck New Tinkertown; thugs, gnolls, or fire elementals could pour out of the Stormwind Stockades; black dragons, satyrs, nightmare green dragons could attack Darnassus; there could be a Dark Iron clan revolt in Iron Forge; and the Burning Crusade could attempt to corrupt and take the populate of Exodar.  And these events could be done in such a way that you could only damage and aggro mobs and the bosses around your character's level.  A level 0 wouldn't be able to get raped by the ?? boss of the raid.  And it wouldn't just have to start at the city.  The raid could march on the city, going across several zones.  And there wouldn't have to be a huge announcement, it could just happen.
There could also be natural disasters, and the relief that goes with.  Fires, floods, earthquakes, storms, rockslides, etc, could happen in zones, to towns.  This could have stuff like during holiday events, like putting out fires, moving rocks, bandaging hurt people, bring/creating food, etc. 
These kinds of things could make all the zones and places more fun to go to, and that gives everyone more stuff to do instead of grind. 

Next Expansion: Underground Zones

The two major enemies of Azeroth are the Burning Legion and the Old Gods.  It's reasonable to assume that the next expansion will have either, or both of these two, as the main villains.  As such, to have more zones for high level play, Blizzard is going to have to find a new place.  I think several underground zones would be idle for the Old God part of the next expansion.  This would be a perfect place to introduce races not already in lore, classes not seen before, and have more lower level content to go with the higher level content.

Day 1

I've done it.  I have become such a nerd that I made a blog about World of Warcraft.  I made this blog to express my new gameplay ideas, in the vain hope someone at Blizzard will read them, like them, and want them. 

This is just a simple post, and not really an idea.  Two nights ago I dreamed that in patch 4.2 during his attack on the World Tree, Ragnaros will consume part of Archimonde and imbibe some of his attributes.  Whether that will happen, has happened, or could happen remains to be seen.