Here's the thing.

If the content was actually as major a roadblock (for casuals) as you make it out to be, the fight would have been changed by now. The reality is, however, that the fight has been left untouched for more than a year already. Had it been a problem, the casuals would have either roared in an outrage until the fight was actually brought to manageable levels or quit the game in frustration which is something the financial team would have noticed.

A similar example can be found in late ARR, when the Steps of Faith was met with major butthurt and foul mood over a simple fight. It was changed, because a LOT of people were either frustrated with the fight design or could not legit clear the fight without being absolutely carried by somewhat decent players.

Without actual proof I am going to call your claim about *most* casuals having difficulties with the fight total bs. Most casuals I know had no problems whatsoever, and the ones that did could pretty easily be carried by perfectly average players through the content, week 1 included. The "problem" has been and will be further alleviated with the increase of gear available for most end-game players.

You call it a NORMAL STATE OF THINGS for people to be wiping to that particular instance and only ever clearing by a number of repetitions and failures. My own experience is the contrary: I don't think I have ever spent more than 30mins in that particular instance, even with really inept and/or new players with me. Maybe my perception of the normal state of things is just deluded, however?

I do not believe that any of the mechanics put in to the fight were designed to be EX level. Even if Stormblood has a track record of making the easiest Extreme primals up to date, Shin NM does not hold a candle to any of them on a mechanical level of things.

Before you deem this as a "White Knight" commentary: I have many problems with the game and disagree with several design decisions implemented in the game as shitty. I have also cleared all relevant content par UCoB. I don't think Shin NM is close to a problem or faulty design, however.

It really annoys me how people write about this subject as if it was some kind of a norm that there's a huge crowds of helpless people out there whose pleas of help are dampened by "White Knighters" (aka people who disagree with you). I might be biased, but you should probably take a step back as well before implying understanding the state of things better than the other people writing here.