What part of Titania was 'more orderly' than Innocence? What part of Zodiark is 'less orderly' than Hyadelyn? I don't understand these random attempts to pair them up you've made, the only way to designate fights is the order you do them in the story, EX1 EX2. It sounds like you're trying to ascribe a design decision to Hyd/Zod based on their Light/Darkness lore thing, which is just weird.
To try and say that (from a lore perspective) Titania, king of pixies, who are known for playing tricks on people and being generally unpredictable in their behavior/temperament, is the 'orderly' fight? And Innocence, the 'literally a being made by the corrupting effect of a pure Order-aligned element (Light, in FFXIV lore)' is the 'not-orderly fight', is nothing more than a case of 'I struggled more with X than Y' in disguise, I think.
But putting the lore aside until the devs confirm at fanfest that 'Yes that was the intention actually', every fight has a certain static structure to it, it's just that some are more obvious than others about it. When you're learning the fight is obviously subjective, some people 'get it' faster than others for stuff, eg Rubi circles. But once you 'know' the fight, then they're always all super predictable and easy to read. Even 'Yolo-diark'
This is the biggest factor, it took me multiple parties to progress and learn Byakko EX, a very 'easy' EX by most people's standards, as I was still kind of new to 'harder content' at that point, and hadn't built the skill of 'see mechanic, interpret what to do' instinct. Fast Forward to SHB launch and after me and the group I did it with watched an overview guide on Titania EX's mechanics, we cleared on the first pull. Does this mean that Titania EX is a joke of an EX fight compared to Byakko? Not in the slightest, it means that over time, I had gotten better at the game (a bit)
It's like One Punch Man, if you do harder content enough, you get too strong for the weaker content and you start perceiving it all as just being a pushover. It'd be fine if it were a pushover that took several different kinds of attacks or techniques to beat, but I play WHM/SGE, all I have is the Glare-Dosis equivalent of 'Consecutive Normal Punches', to continue the analogy