Most of the Stormblood fights have been fun because most of the time it's easy to tell what to do because there's clear indicators, voice/audio cues and the like, but some of the new fights have mechanics that are rough to figure out for the wrong reasons.
There's already been a thread about Starboard/Lardboard in Alphascape v3 and I can't imagine how much of a pain it is for dyslexic people because there is literally no other indicator besides the text and the words look pretty similar. Even worse is that I play with 2 Japanese players and the attacks are seriously just called Left/Right lasers in Japanese, so why was this mechanic made more annoying to figure out in other languages for no reason other than flavor? I also play with a German player and not even THAT language was safe from this.
There's some problems with v4 as well. Why aren't the icons used in the final phase just Blue Male/Pink Female symbol instead of the weird body shape icons we have now? That way the icon would be way different and also the color would help people recognize it more quickly. You could have also just made the female symbol more curved if you insist on using the ones you have now.
On top of that that phase has a mechanic where the bosses are buffed up if they are close to each other that we didn't notice for a few attempts because it's only indicated by a buff icon on the boss' status bars instead of a tether like everything else in this expansion so far. It's not like it makes the mechanic any difficult. On top of that it is easy to miss if the boss has a lot of dots and such on it, and the boss already has a mostly useless buff that tells you what form it is in that makes it easy to just filter out the "too close to the other one" buff.