The issue here is a common one where the devs listened to the community but the community is stupid and doesn't actually know what they need or want.
Unfortunately the relative inexperience of Yoshi's team is showing here. 99% of the time, the community is both stupid and wrong. The first thing MMO developers need to learn is to focus on the data they have gathered and ignore what the community is saying or doing. The data for original Coil showed around a 10% completion rate before expac for JP and around 4% for NA/EU. For anyone who cares, the average WoW raid completion rate is not far off that mark in the NA/EU regions, although WoW is not and has never been officially available in JP.
Coil's difficulty was appropriate for the community, which is why Alex Savage such a bonehead fucking retarded design decision. FFXIV is not a hardcore raiding game, all the hardcore raiders play WoW. The fact that the vast majority of hardcore raiders have had to congregate on one server (Gilgamesh) just to find each other should be proof enough that the hardcore raiding community is tiny in this game.
Of course one big problem in FFXIV is carried over from FFXI. Yoshi and his team live in a bubble where only the JP community is ever considered. There was this one time where Yoshi was at some convention in the US and he sat down to play a Ninja character and he was like "Why is it laggy like this?" only to be told "Oh, that's normal." Like he had no fucking idea that mudras had lag, because he and his team only ever played on the JP test and live servers. So maybe they thought Coil was too easy because 10% of JPs had cleared it before expac, more than double the number of NA/EU players.
Was going to post a pretty long response to some stuff an hour or so ago, but decided maybe I didn't need to. One of the points was how I love single player RPGs so much for those times I screw up mechanics but still somehow manage to pull off the win on a first play through. Most single player games do not require a high degree of skill/execution/strategy to win the battle on a first play through, and you can get by with a messy, impromptu plan of action to try to salvage things. FF XIV's raids do not allow for this until you are overgeared. During progression, rarely, if ever, can you overcome a decent mistake. That sucks so much of the fun out of the fight for me. And yes, with a fight that's 10+ minutes long, that sucks. I can deal with that on a smaller scale (see hard platformers, character action games) where the restart penalty doesn't suck because the thing you're trying to overcome only lasts a few mins long at most. The requirement that a single mistake can ruin the run/fight only applies to harder difficulty settings or self-imposed challenges, which is what you do AFTER you know a fight very well and have been clearing it a lot. MMO raid design is like the complete opposite of this, especially in FF XIV, because it has to for the sake of keeping people playing...er paying longer. It's probably the single thing I hate the most about MMO raiding. Compound this with the fact 7 other people can make mistakes (ie it's not just you), and yea...it's frustrating. Which is why I've stuck to single player games for most of my life and have hated any type of co-op ever conceived.
The cycle of the MMO raider more or less goes:
-----> START PLAYING GAME
(1) OMG this is fun we're doing all this shit together WOOOOO
(2) Damn, I've been at this awhile and my only reward is more of the same
(3) I like doing this because I'm friends with these people and we've been together forever
(4) This isn't as much fun as it used to be, but I gotta stick with my friends
(5) I'm bored of this shit, I've been doing it for months/years
(6) Goddammit I don't want to quit, I don't want to leave my friends behind
(7) Fuck this shit
----> QUIT GAME OR GO CASUAL
There's a reason why most WoW raiders will raid for some time, possibly years. Then one day they stop and never raid again. Some quit the game forever. Others return just for big patches to see the story. The entire MMO raiding cycle is based on new raiders joining the game and raiding when old raiders quit. When the total number of raiders in the world is exhausted, you see what's happening with WoW where subs peaked at WotLK and have been spiraling downwards since, only to spike for a month when an expac is released. More people are quitting raiding than starting raiding, and all the other players just resub for the expac, look around and see the story, and go back into hibernation.
Squenix has managed to compress the 10-year long WoW cycle of growth, peak, and decline into just 2 years by releasing such a disappointing expac in HW. Good job there I guess, but this is one case where you don't want to be better than Blizzard.