You took what I said differently. I'm not saying that it doesnt make sense a fury warrior cant use ashbringer. I'm saying that if all mogs are bnet account wide then my 110 rogue on wow1 who has access to all tmogs and artifacts, then my 110 rogue on wow2 should also have access to all tmogs and artifacts. HE does have access to all tmogs but not artifacts. If that's intention then you should not be able to tmog alts at all if it character specific.
Got an answer from a blue, basicly they said since 8.0 you have to log into the original character that unlocked it once before an alt can use it. So if your main account has run out of game time or w.e the issue is you CANNOT use artifact tmogs on other characters. 10/10 blizz great job.