The many Divine sprites exploding and doing global raidwide damage after being defeated is pretty good, gives me a bit more reminiscent feelings to ivalice's exploding mobs, but scaled appropriately for Lv 90.
There were a couple of DoT bleeds that did hit what I consider a good enough damage for a DoT bleed if you also take into account of its long duration at the current ILVL. Stepping outside of Llymlaen's stage will apply a uncleansable Drowsy DoT debuff that lasts for 21 seconds -- and while the DoT damage didn't hurt too much on its own on a healer/dps, it did a pretty significant amount over a long period of time, making it a good way to keep healers healing a bit more often but without too much pressure.
Torrential Tridents did too low damage landing down. The staggered intervals of damage is fine, but it barely needed any healing for the long wind-up time before the next run-around-and-dodge-aoe mechanic. Bumping up the damage per spear would be fine considering it already barely tickles at the current ilvl without mitigation and my cohealer just needed 1 rapture to bring everyone back to full hp after all the spears landed.
When Oschon was using Lofty Peaks, me and my co-healer sort of expected something more akin to P10N's Harrowing Hell's amount of damage, so both Panhaima and Liturgy of the Bell was used. What we got instead felt much weaker and more of a joke. Even the finishing attack Peak Peril couldn't break through the Panhaima shields (had over 3 stacks remaining) and liturgy was 100% wasted. Quite disappointing.
The Final Boss using Eudaimon Eorzea, just the channel before the cast finishes doing damage makes it much better in terms of damage frequency and heal check.