Its soft because the swap can happen at one of several points rather than a swap must occur at this one point. Depending on dps it was actually possible to avoid some swaps as the debuff would fall of while Ultima Weapon was doing a phase transition cast.
The explosion was an AoE but it hardly covered the full battlefield. The Spiny randomly targeting the person that was either number 1 or number 2 in enmity (due to most OTs not holding spot 2 on the enmity list it would randomly go after the healer) and the wipe mostly occurred if it chased after a healer during a sisters phase and the tanks didn't grab it of the healer at the right time. They have not repeated it in full due to the Spiny being too easy to kill with random ogcd AoEs and post-provoke shield lobs/tomahawks and the NA/EU playerbase coming up with an unintended tank arrangement for the sisters which caused problems with the swaps.Spiny Plume -> The penalty for not swapping the Spiny Plume wasn't against the tanks, it was a hard party wide bust for tank incompetence. If you got three stacks, you would explode causing massive damage to everyone, generally only survivable with VIT melded accessories/latency/raise luck. This is a unique mechanic that I have not seen repeated in this fashion.
The tank tether only occurred during Nails and was more there to force the OT and tethered dps to stay in proximity while the dps was on the nails. If you swapped just before the phase started the tether was rarely a problem because the tether would end before the other tank got full stacks. It was more a problem if the MT went into the phase with 2 or more stacks potentially forcing them to tank with max stacks until the tether ended.Ifrit Ex -> Due to the chain tether, swapping was controlled by the fight, often requiring a tank to take the full 5 stacks of Suppuration, and to try and swap while the OT still had the chain would result in the chained tank's death.
Feeding was an intended mechanic but number of Spiders fed and how damaged they were before feeding was supposed to be a variable in strategies. You had plenty of time to kill 1 or 2 Spiders before feeding the rest to the first Dreadnaught without running out of TP, but feeding them all from the start was faster and only really possible with the durability of a Vit Paladin.Turn 4 Dreadnaughts -> The first Dreadnaught needed to eat the 4 spiders, because otherwise physical DPS would go resource dry, necessitating resource singing, lowering raid DPS, failing the overall DPS check of the fight. This phase was proceeded by the double Spinner Rook + 4 spider phase, so you needed to have resource for AOEing that. The only Dreadnaught not fed spiders in this fight would be the second one, ideally.
That was mostly because T8 expected the party to be in full weathered tomestone or better gear. Weapon upgrades were locked behind RNG (Wave/Tidalwave (no tokens here to guarantee) and Animus relics) or multiple weeks of tomestone grinding (Soldiery weapons). The OT swapping to Strength accessories was an easy way to boost average party dps especial since T6 and T7 could be stingy and drop only Fending and Healing accessories multiple weeks in a row.The tank meta "changed" starting in Second Coil. DPS checks started to really ramp up then, and it became apparent that not a lot of people were up to them, resulting in many groups only using two tanks if absolutely necessary, in order to have more DPS in the group. Tanks also started regularly full timing either pentamelded i70 accessories or STR accessories entirely, in order to help meet these checks. The Turn 8 boss was the first boss in the game to have over 1 million HP, having about 1.01 million HP iirc. There was also a Dreadnaught add with just under 100k HP. With a hard enrage time of 11 minutes, this meant the raid needed to do one hundred thousand damage every minute. This required a raid DPS of somewhere in the ballpark of 2000, and a good DPS at the time in entry level gear was capable of roughly 300~400. A good tank, in entry level gear, but with STR or Pentamelded accessories was sitting around 200~250. Every little bit mattered.
A lack of regularly occurring big hit psuedo-busters is one of my biggest complaints about modern fight design. No reason for the healer to keep the MT topped off if no attack in the next 30s can threaten them and we can't get much use out of Tenacity and Sheltron/Raw Intuition/Heart of Stone/The Blackest Night when all the tankbusters are covered by Rampart, 30% cooldowns and invulns.
That formation also left Provoke free for use to swap the Spiny at less risk of a mistake.Garuda Ex was unintentionally really interesting. It just so happens that NA/EU players did the fight incorrectly and brute forced it. You were supposed to have Garuda on one tank, Superna on the other, and Chirada on the dps who stacked for downburst. Double Wicked Wheels were never supposed to be a thing.
Stack resets also happened with the phase transitions if they occurred slightly before Mountain Buster was coming up in Titan's rotation. If your dps were good enough and MT tough enough, you didn't need to tank swap or use Hallowed Ground until phase 4.Titan Ex solo tanking was a function of the fact that Hallowed was broken at the time and prevented stack application, allowing for stack resets.
Death Sentence came out too often for that as Provoke was on a 40s cooldown. Every so often you were forced to take 2 Death Sentences between swaps.Twintania was meant to force a swap on Death Sentence with the healing debuff. We just happened to ignore it with Lustrate.
Also factor in that DpS could use the optional adds to reduce the damage up stacks and you have a fight were better mitigation and healing means greater dps output on the boss.T1/Caduceus is really the only one of these which doesn't really follow the current pattern. Irregular arena. Soft enrage where your tanks rotate cooldowns until the boss dies or the tank dies. It's incredibly simple, and yet it does mitigation in a way that's somewhat interesting. And invulns aren't quite so overpowered in this sort of scenario.