Hoo boy, don’t get me started on that. 
Funny, that’s exactly how we ended up here. People kept asking Funcom to “make legendaries legendary again” and here we are, because Funcom has only one way of rebalancing:
What you say about Khari, Dagon, Telith, and similar is true, but it requires more careful balancing, with attention to detail.
Although, to be fair, there is no way to satisfy the most strident fans of slot machine mechanics except by making legendaries superior to every other weapon. Make the Telith’s Sorrow better than the Blade of the Adventurer, and you’ll get screaming hordes here whining about how it’s unfair that they had to grind for days to get something that isn’t as good as a sword anyone could craft. But when I dare suggest that the problem is the bloody RNG and Funcom’s overreliance on it, nobody freaking listens, because that’s the way it’s supposed to work. 
So call me bitter and petty, but anyone who kept screaming for the legendaries to be “legendary again” and at the same time remain RNG-gated to the same ridiculous degree got exactly what they deserve.
And I keep trying to tell people they’re holding rarity sacred for no reason. Why do people think a rare drop is valuable? Because it took them time to get it, and they conflate time with challenge.
Yeah, you gave Telith’s to all your thralls, but you had to farm the keep to do it. The more thralls needed Telith’s, the more time you had to spend on the Black Keep, and you couldn’t spend that time on anything else.
Bingo!
The counterargument to that is that the Kinscourge isn’t particularly harder to kill than “an easy boss in the UC”, and yet that UC boss RNG-gates its drop, whereas you always get the heart of Kinscourge. 
But those complaints about relative difficulty also end up backfiring on us. I remember the “make legendaries legendary” debates and offering the counterargument that it’s ridiculously easy to get the legendaries that drop from the world bosses. Well, take that counterargument and combine it with complaints about jerks who like to build on top of legendary chests and what do you get? More grind, because now those chests are inside dungeons.
So maybe I shouldn’t really even voice that counterargument about always getting the heart of Kinscourge, lest devs get the idea that maybe the hearts should drop randomly 
The more we talk about this, the clearer it is that there is no solution without revamping the way legendaries are obtained. As long as you have RNG “challenge” in one corner and deterministic challenges in the other, you’ll have people yelling at each other that their way is better and deserves more consideration.