For the Zoraal Ja EX fight, I can't remember exactly what my friend said (I didn't really inquire further myself and respected their wish not to run that fight, but I think they said it was something about how you have to spin your camera around a lot to track the fire lines in that one middle part? I've only cleared the fight once, so I'm kind of rusty on what exactly it was. Something about having to track lines while moving the camera around though, I think.
For Sphene EX, once again, didn't inquire exactly what the problem was on a detailed level, only that it had something to do with the lights or effects going off causing eyestrain and headaches after more than a one or two pulls.
I've mostly been unaffected by the changes beyond thinking all the bloom effects are ugly and disliking the new "improved" character models, so I can't speak to my friends' experiences. But I felt I should chime in to say that even a person like me who hasn't been getting headaches or motion sickness is still being negatively affected by these graphical changes because the people I play with regularly are dealing with adverse effects that keep us from running content together, because I'm not going to force my buddies to run fights if it's causing them so much physical distress.