I always wondered why they didn't phase the various eras of wow. So, for example, you play vanilla, then you get to TBC content, then WOTLK, etc etc. I can understand that there would be considerations of segregating playerbase, but they could keep the capitals as one area and just phase the rest, surely?
I don't get why Blizzard seem fine with Outland content to be honest. There was an interview with on of the content designers a few months ago and he basically said that Outland was still much more fun than vanilla Azeroth so they didn't see an urgent rush to revamp it all.
It's horribly tedious to play through now a days and I still think having Death Knights start at 58 is one of the biggest mistakes they have made.
My continuity alarms start ringing when I think of Pandarens killing Illidan, or killing Arthas after the Cataclysm.
The perils of having a static storyline in a persistent world.