You can also have really shitty luck. I tried going for that achievement, but fuck me... some of those fuckers seemed like they would never spawn or someone was camping them more than I was.
Its not that bad anymore. Not by a long shot. Weekly points have an end of expansion buff on them. So you get your 1k per week in a fraction of the time. Runestones, sigils, all that shit has a much higher drop chance now, too. Its likely he'll finish in the time period hes thinking.
The only thing is, the cloak isnt going to last as long as people think. "DUNGEON" gear at 100 is 70? 75? ilvls higher than the Cloak, iirc. Even with the effect, it just isnt that good at 100 unfortunately. You're suppose to be able to continue the Cloak Quest line? But thats just a theory. Cause if we know we have a Legendary ring quest.. If the quests are as easy as the MoP Cloak Legendary Quest, and those Legendaries are BiS... .. I guess what Im trying to say is that it seems like it would be fucking lazy to have a legendary quest for both a ring, a cloak, and whatever else they have. Its no longer legendary in my mind, then. Just 50 less items that they have to design at max level.