As obnoxious as those "Go play PvP/WoW" comments are... they do make a point.
This game was built primarily for PvP. The game system was built to best accomidate it. It's also not a P2P game, meaning they have limited resources when it comes to updates. P2P MMORPGs tend to cater to PvE and have the funds to make the in-game worlds persistant and ever-changing. This helps prevent the game from stagnating. So, I guess you get what you pay for in that respect. Now, when people say "Go play WoW", what they really mean is "Maybe a P2P MMORPG would better accomidate your gaming-needs"?
To be fair, the "Go play PvP" comments do make a fair point, too. You're eating half of your lunch and asking for more. PvP is basically the true 'end-game' of Guild Wars. PvE is static, think of the chapters as Novels (however badly written). Complaining that you don't get new PvE content is a little short-sighted as that's the bulk of the content in the new chapters.
Why is PvE static? Because it's not dynamic. Why is PvE not dynamic? Because it's not a persistant in-game world. Why is it not a persistant in-game world? Because GWs isn't a MMORPG.
Dispite what people say, GW is no more of an MMORPG than Diablo II. When you compare the two, towns and outposts in GW act pretty much just like chat channels in Diablo II. They both lack one of the defining elements of a MMORPG, the persistant in-game world.
I'd just like to remind you that it's all part of the same game. Story Mode, which everyone should play at least once IMO, and PvP, the core* of the game. The whole PvE/PvP animosity is really quite pathetic.
*I mean that almost litterally. Since all the new chapters are selling 'Core' + 'Prophecies/Factions/Nightfall'. 'Core' basically being the game mechanics and the Battle Isles.
Okay, I'm going to shut up now.