Because from a game lore point of view, your character who goes through this storyline and saves the world is considered a "legend". Doesn't really matter if you play the storyline on easy or super hard.
Also, I don't have any numbers here, but we dirty casuals probably make up the majority of WoW players, it's a good idea to keep us involved. Unless this is solely a matter of color because orange is supposed to be super speshul, in which case, sure, okay, make the ring purple, I wouldn't care. iLvl too high ? Well, shit, the rest of my gear is like iLvl 655 at best, so I think you're safe.
With that said, I think it would be great if they added other legendaries only available in Mythic.
Do people forget Legendaries in BC just dropped from the bosses without having to do anything besides you know killing them.
well, you get tier sets while lfr have those crappy lfr tier sets. guess its not enough for actuall raiders, and the little effort we have to put in makes the rewards to good ? i dont get why people are complaining that lfr drop gear, while it drops the worst gear in the game. everyone will basicly be forced to run lfr to get the legendary, and the guys that want to look at higher difficulties wont be able to get into raid groups because you have lfr gear, and dont have the legendary ring. it was the same crap with the legendary cape in mop, without the cloak there was no way in hell you could get into flex pug groups. removing the legendary quest objectives and drops needed from lfr would have just made the gap bigger, which is a really bad idea.
The legandary ring, just like the legendary cloak, is just a mechanism made by Blizzard to get you to stay subscribed throughout the expansion, or at the very least, get you to come back with a patch.
It's meant to be available to everyone.
I hope they eventually create an old-style like legendary to go with it.
There is no Bad RNG just Bad LTP