You challenged us to name one thing that is persistent in Guild Wars. At the close of every BWE, the devs sprang some sort of surprise on the players. Last month it was gift boxes full of gnomes, fireworks, and celebration. The month before it was an invasion of Gwen's that firebombed everyone while quoting Blade Runner. Those events happened simultaneously for everyong that was ONLINE. I missed one of those two events, so I have proof that they happened regardless of whether I (or anyone for that matter) was there or not.
Great, so there was a worldwide event in which the whole world experienced fireworks and gnomes falling from the sky in presents. I guess that makes Guild Wars a completely persistent title regardless of the fact that 100% of the game world isn't persistent with the exception of the BWE end event.
Let's lump Guild Wars in with all the other MMOs because it's an online game. Guess that would make CounterStrike and UT2004 MMOFPS. Lots of people playing it at the same time, after all - and as for persistent gameplay? Every time Valve releases a new update, everyone has to download it!