Hey guys!
So, there is a thing called.:
which unlocks all of the challenge mode weapons with no regards to what class buys it, as long as you have the proper achievement from back then.
So why don’t Blizzard implement a similar Arsenal: Mist of Pandaria Challenger’s Armor for the people who earned:
which could unlock all the different class sets? As long as you have the achievement, of course.
I agree,
Anyway there’s a vendor for those who complete the Challenge Mode in MOP who sell the pieces, but you can buy that set only if the license is still available.
In the US forum there’s one answer from CS about this topic:
because it’s all about the achievement, for exemple i got my license suspended BUT on the account i got every teleport and even the Mistwalker title account-wide and not anymore locked on the one character who earn that!
Yea, I know the vendor, but it only sells me the Rogue armor, as it was my Rogue I earned the achievement on. 
It should unlock all the different sets…
Well I think that will be too much.
Not at all, I think it’s just as appropiate as getting all the different weapons in WoD.