Does WoW use PvP as filler between expansions?

I've noticed with the recent release of Wrath of the Lich King that a lot of people have started changing their minds about World of Warcraft. The game had been getting negative criticism about lack of innovation and poorly designed PvP systems. Some players hated that arenas had become the primary way of earning gear and that Blizzard was heavily promoting their game as an e-sport. Now all seems to be forgiven though as Blizzard is back to handing out highly polished PvE content. In fact initial impressions are probably even more favorable for this expansion. The difficultly level is more in tune with the majority of the playerbase and the lore is more traditional. No alien space paladins crashing their dimensional ship this time around.

Still it's only a matter of time before a majority of the player population once again reaches level 80 and starts in on the end-game. While raiding will probably be popular you can also expect arenas to make a come back. No really knows if they will once again become the primary focus of the game though. Remember the Burning Crusade raid progression was severely messed up and Blizzard hadn't yet put rating requirements on all the PvP gear. These two factors might help prevent arenas from dominating the end game like they did at level 70. I know a lot raiders felt that arenas steered players away from raiding and this probably generated a lot of negativity about the future of Worldof Warcraft.

Developers have to remember that players follow the path of least resistance. I hate quoting Raph Koster but I'm sure he said something along the lines of "Given a chance players will optimize the fun out of a game to achieve the fastest progression." Blizzard failed to account for how difficult it was to organize raids and how much easier arena rewards were to attain because they didn't require one. On paper the rewards for arenas and raids might have looked similar, but that wasn't the case in the game. Keeping a guild together while it made its way past Karazhan was a monumental challenge and pick-up-groups could often only do the first couple of bosses. Hopefully, history won't repeat itself with this expansion. Blizzard seems to be better at balancing the rewards and I think arenas and raiding can prosper side by side.

After all it's not like Blizzard can just ignore the demand for PvP content. Age of Conan and Warhammer both had impressive sales due to the fact that players now have an appetite for PvP in their MMOs. Plus PvP content usually requires fewer artists and developers then a new raid zone. I think Blizzard effectively used the arena seasons to keep people interested in the game and freed up some developers so they could work on other projects. That's not to say its easier to develop PvP content just that it requires less maintenance to keep it current. Once you have the reward system working in balance with other parts of the game, PvP systems are simple to keep updated. However, I don't think people play World of Warcraft for the arena seasons. Wrath of the Lich King has pretty much shown us that World of Warcraft is still the PvE King.