I mean, moreover, the toast text is only very rarely useful to actually reading fight mechanics; yes, sometimes you have fight-specific mechanics that are telegraphed in text, most notably Cutter's Cry with the "The ram's eyes burn blue." and "The dragon's eyes burn violet."
And while you can make it easier for sprouts in that fight by giving them mnemonics ("If it's violet, stay by it; if it's blue, better shoo!"), those are only useful for that fight and there are many, many, many other chimeras (or garms, or shadowcourt hounds, or...) in the game. Far better to teach them that it's the Ram's Voice / Dragon's Voice cast to watch for, and a mnemonic like "Ram means scram." to remember that Ram's Voice is the point-blank AoE you want to get the hell away from (and that Dragon's Voice is thus the donut).
But 90% of the time, if that toast goes off in battle, it's something like "Totomu has returned from his venture!" or "The <random crafted thing> you listed on the marketboard has sold for <some amount of gil>."
Which, I promise you, is not information I need mid-pull in P4S or whatever. Certainly not in large print, right dead-center on my screen. Hesperos does not care if my retainer brought back more Grade 3 Thanalan Topsoil for the FC gardens, so -- at that particular moment -- neither do I.
There are, so far as I can tell, actual (semi-rational) reasons for the alliances being separated, at least. Not least of which is that if you treated all 24 as one party UI-wise, controller users who need to be able to zip through the party list quickly to target people would be trapped in a nightmare when they needed to heal or rez someone.
But the fact that there's sound reasoning behind it doesn't make it less annoying if you need to try to select someone in a different alliance in order to rez their healer or whatever; with default bindings, you pretty much have to just mouseover and click on the person in the little alliance windows.
It is possible to make saner selection logic with KB+M even in the stock game without mods, though.
For instance, FFXIV actually lets you bind selection parameters to the scroll wheel of your mouse. As a result, I have the mouse wheel set to scroll through the enemy list, Alt+Scroll Wheel scrolls through my party list, and Shift+Scroll Wheel will go through my party and the alliances. Control+Scroll Wheel is my actual zoom in/out. Having done this for more than a year and a half, I can very quickly select precisely which target I want (though if I ever replace my mouse with something that has different scroll wheel sensitivity I will be screwed).
I find that's been useful to pick targets to heal/rez quickly, and it's also proven surprisingly useful in PvP. (The enemy team in Crystalline Conflict is, internally, apparently a reskinned aggro list and thus my scroll wheel bindings function on it, leaving me able to select a specific enemy near-instantly with the scroll wheel.)
Yeah, the fact that party buffs/debuffs are generally fairly... compact unless you make the party list ginormous is not ideal. I admit I don't personally have a problem with it -- I actually run the party list at 80% size rather than enlarged -- but I also know that's not a universal experience by any stretch.
Were I designing the game, my accessibility approach would probably to add an additional (optional) UI widget which would show only a subset of the party list -- specifically anyone other than you with a debuff that can be cleansed (or healed to clear), and yourself if you had any debuffs at all. I feel like that would make it much easier for vision-impaired healers both to spot who they could do something for (not necessarily have to, because it would also presumably show things like weak/meaningless poison debuffs that last a shorter time than it would take you to cleanse the party), and to read their own debuffs at a larger size for mechanics where those debuffs really matter, like the Relativity mechanics in E12S phase 2.
But I will also concede that many, many games do not approach accessibility considerations at the beginning of design, and it can be a real pain to add some aspects in after the fact. And even when you do try to approach it from the beginning, it takes time -- and you still won't manage a good solution to every scenario. (Moreover, you can't come up with a good solution to every scenario, not without potentially nerfing the game difficulty in someplaces. Accessibility that eliminates unintentional challenge -- e.g. "your UI sucks if the player has impaired vision/colorblindness/whatever" -- while preserving intentional challenge -- i.e. fight design and whatnot -- is a tricky balance to strike.)
I mean, even in my own case, it was specifically the fact that I made a gaming friend who was almost entirely deaf, and that one of my best friends in WildStar had severe nerve damage to his hands, which taught me to approach game design from an accessibility standpoint. And that was well after I was no longer writing games for my day job; by then, I was only doing so in my spare time as a lower-stress (e.g. crunch-time-free) hobby.