So what you want, is a system that is completely random and luck based, to give the player who was fortunate enough a massive increase in DPS through no effort on their own, and puts them on a pedestal unobtainable by others unless they get the same kind of luck
...Wait that's Corruption. Didn't we just finish explaining in 20+ seperate threads on why corruption is bad and it toxified the game?
Legiondairies and Shadowlands Legendaries are, while seperate entities, still more fair in their current itteration, then both this random luck of a chance that is corruption, and old school legendaries. You can farm for specific things that help alter your playstyle in interesting ways akin to Azerite Armour and our Talent Rows.
As a reminder, Shadowlands Legendaries aren't a RnG drop, you have to craft them yourself.