The truly difficult fights in most FF games are optional ones, not part of the core story progression. In FFIV, Bahamut would be precisely one such example. It's the FFXIV equivalent of the MSQ itself being "easy" while providing a variety of other optional content that increases in difficulty. (And there's a bit of irony in mentioning Zeromus, given how Square intentionally and significantly nerfed things in making the "EasyType" version of FFIV that was sold in America...)
It's one of those "things change over time" deals. MMO's are long past their "golden era". We are never going to see something like WoW having 12 million active subscribers again (heck, WoW needed to put out two "solid" expansions in a row just to reach ~2 million). The simple reality is that MMO's are no longer a "second life" for the majority of its playerbase. They're no longer new. They're no longer the most convenient space to interact with others through a device (Instagram, Snapchat, etc. all make those connections much easier today). And the playerbase itself on average is older, too. It's no longer primarily college kids and young adults able and eager to spend hours upon hours a day in an MMO. It's now mainly adults with families and full-time careers who pop on for maybe an hour a night and want to feel like they've accomplished something during that time.All content should be like this in MMOs. Ironically people are complaining about the genre of game they are playing.
This is a prime example of how constant calls for nerfing the game ruined it. People's first solution is to always complain and hope the developers lobotomize the game instead of socializing and working together.
I fondly remember playing WoW in 2005 and shouting in XR to get a group together for Wailing Caverns, walking over to the dungeon, and then spending potentially up to 2 hours completing it. I also can't even imagine wanting to do that today. The game isn't being "ruined" for the majority of its playerbase by making things easier. It's adapting to that playerbase, and leaving behind those who are, sadly, stuck in a past world that largely no longer exists.