So going after the legendary mace Val’anyr, Hammer of Ancient Kings and well was curious about how long it’s taken other people to get it and whether there’s and tips for acquiring these Fragments 
But did my first run yesterday after hitting 60 and managed to get ony 2/30 doing all bosses except two on hard mode being XT-002 cause I instinctually casted flame shock which finished them off before I could destroy the heart and The Assembly of Iron cause the big guy just died randomly after I killed one of the other guys so 
Took me forever, but I wasn’t trying anything specific, just clearing weekly.
most peoples experiences are probably going to be invalidated by the fact that there’s no 10/25 anymore.
fragment drop rates either lowered significantly, or RNG became more of a meanie-head once 10 became the only option.
Oh oof apparently hard mode helps but supposedly its a 10% drop on all bosses except Yogg who has a 50% drop chance.
But need Wisdoms Hold from Thorim and the Legendary Mace for my Transmog so yeah will be doin a lot of Uldum already parked my Vulpera tent out front but at least mace will also be useful for WotLK and I think BC timewalking 