These are the problems with having anything exclusive in an mmo, especially like wow which houses a very prominent casual raider crowd. You either cater to one of your largest sources of income, or continue to treat them poorly. It's about money, really, but more than that exclusivity is a good and a bad thing. Case and point I've seen 3 people total, ever having Val'nyr. Why? Because it was so difficult to get and every healer and their mother wanted shards. I've seen more people with the AQ battle-tank than I've seen with Val'nyr, though that's my personal experience and shouldn't detriment from the actual number of people with said two "legendary" items.
Further more, legendaries based on "luck" is... well let me put it plainly, it's fucking stupid. Take a look at GW2 legendaries. very little is involved with RNG. Want to know how to get GW2 legendaries? 200 hours (plus or minus) worth of work, including completing every map in the world, doing a shit ton of dungeons and wvwvw and just overall being a badass at the game. I, personally was really glad that the dev team started to push away from the super rng of legendaries, even though sigils, secrets and runestones are all RNG locked on a weekly lockout.
Lastly, what makes a legendary, legendary are multiple key factors. First of all, it's look. It has to look badass, I'm talking Mr.Torgue badass. Secondly, it has to feel like you spent enough time on it to warrant it being legendary, while at the same time not feeling pointlessly being cock blocked by rng (I'm looking at you second binding of thunderfury, Val'nyr fragments, glaives, bow, ect.) After a while a player will get sick of "will it drop, won't it drop, nyaahhhh". Discouraged players breed losses in subs. And third, and the final aspect of what makes a legendary, legendary, is the story behind it. Not only does it have to look badass, feel like it was worth it without over doing it, but it also needs to have a driving point in the lore. It needs to have a good story behind it with as much badassery as possible.
I'm not saying the cloaks accomplish all this, but not a lot of other legendaries do that either. Fangs of the Father, Tarecgosa, smourne and Sulfuras (strangely enough) all embody the three things that make legendaries, legendary. Sure, glaives have solid lore behind them and their look backs it up, but being rng blocked is the worst feeling. Same with the bow minus solid lore, as it's not exactly clear where the bow came from and wasn't exactly iconic like the Glaives or Smourne was for an expansion.
If I had to say two things I'm disappointed in the cloaks is the fact they are cloaks, and thus fuck with my xmoggs and have very loose lore behind them. -Granted- I do realize you and Wrathion have been spending all expansion making this badass thing, however it just doesn't really have iconic lore behind it other than "You made it, you are the lore", because that can be said for the turkey and biscuits I made last night.