Karazhan is getting beat into the ground nightly by almost everyone on the realms -- isn't it about time, asks Heavymetal from Sargeras, that Blizzard lowered the timer? It certainly seems like the time has almost come -- by the time the last expansion released, UBRS, which was basically the precursor to Karazhan, had no timer and was getting raided like crazy. All of the gear is going to be replaced anyway, and the attunement's been lifted -- why not let players go nuts on Medivh's old stomping grounds?
Bornakk closes the thread due to caps, but we'll play devil's advocate and try to answer for him: Badges. With Karazhan basically a knockover for even beginner guilds, the only way Blizzard has to control the flow of badges from there is to keep the instance on a timer. The Kara gear might get replaced, but some of the Badge gear has to last for a while, and while Heroics do grant Badges (they're on a timer as well), Kara hands out more of them for free than those old ladies with meat on toothpicks at the grocery store.
Still, in Wrath we're probably looking at an all new Badge system, so you'd think Blizzard might as well open the floodgates at some point. Whether it'll be before or after the next expansion, though, we have no idea.