A lot of friends who are casuals came back to complete the storyline. After dealing with spending 10-30min just trying to enter a fight and wiping 10+ times to AOEs most have just left again. A couple have basically said they don't even want to try 2.0 because it will just be the same problems with a new world.
While I do think that this is an awesome fight, for the population FFXIV has (60% only return at patches for a week, 20% full time casual 10% semi-hardcore and 10% hardcore, this fight seems pretty imbalanced.
In 2.0 I would understand fights being designed for hardcores or semi-hardcores. But for the ending of FFXIV which is supposed to let people finish up a story so they can transition to 2.0, this fight seems like its too much of a hassle.
That combined with "unable to proceed due to server congestion" is probably driving a lot of people away.
It also doesn't help that you get the same server lag as with ifrit, which is different for every individual. For example, the first few times i did the fight i got slammed with the beam attack even though i was behind the guy on my screen. I had to watch the minimap and move before he even appeared to avoid it.
Honestly I think that SE should just easy-mode the fight (cut difficulty by 50%?) so that people returning for a few days can finish up the storyline (even if they suck or only have af). If not, it will just make people more weary about 2.0.