I've heard World of Warcraft referred to as the first of a new generation of MMORPGs, which is something I've agreed with, though typically I've placed City of Heroes as the jumpstart and WoW as the foundation. But now I find myself questioning that.

Perhaps WoW and CoH are actually the last of the previous / first wave.

Graphically, there's no doubt that CoH was leaps and bounds ahead of other MMOs when it was released. And Blizzard's stunning art direction and seamless world was a huge advance. But in gameplay, neither of these presented much that was new. Blizzard did what they do best, they took an existing genre and capitalized on it with a slick and polished product. They mostly refined what was already defined, following steadfastly in the footsteps of Everquest.

Between the two, the most advanced gameplay features I can think of are CoH's Sidekicking and WoW's complex threat / aggro system.

Now however, we're on the verge of the true new wave of MMOs, each one presenting some distinct new factors in gameplay combined with cutting edge graphics and combat.

• Pirates of the Burning Sea involves sea battle content with a clever port contention twist which is unlike anything I've seen in these games.
• Age of Conan promotes guild communities with player cities and guild fortifications that introduce real siege warfare. It also includes an inventive combo-combat system and a MUD-style bounty system for PvP.
• Warhammer Online integrates faction warfare with their quest system in an attempt to blend PvE and PvP gameplay together.

There are probably examples from different games that show how the next generation is pushing some real innovations. Bioware's un-named MMO is bound to have some surprises for sure.