Nerfing the tank and DPS party mitigation would get the job done too. Although ... we immediately get met with resistance and backlash if that is the only method we use ... >.> It was what ForsakenRoe mentioned, so she thought that buffing the encounter damage more would be accepted more or not noticed as much. It may seem like a roundabout way to fix the problem, but maybe it can add some more new mechs for us to have fun with if Square can pull it off. Plus using only a full on nerf might have unintended consequences of making the easy soloing stuff more harder than intended. The solo instances would be okay with that WoL self heal buff, but other stuff like solo Hunts, Treasure Chests and FATEs may be a different story.

I can see the other side of it where the tanks and DPS do want to help somewhat with the damage taken too. We could find a midway point where all the roles can do something to help solve a mech. These are some other ideas to consider too. We may still need to consider slightly nerfing some mitigations and self heals, but it might only be a small amount if the encounters are actually hurting the tanks and party members enough. After all, accidentally making the self heals as pitiful as the 1K critical Physick SMN GCD heal is not a curse I want to inflict on anyone.

1. Increase the frequency of tank busters

The fact that the tanks can kitchen sink cooldowns and still be fine is a problem I can read. Typically, tanks are supposed to stagger their cooldown use one at a time for longevity rather than taking almost no damage for 10 - 20 seconds, then suddenly get hammered afterwards. It may still have to be frequent enough so the tanks don't just simply provoke swap every minute and still kitchen sink it. If we do want swaps, Warcraft often times used a stacking vuln debuff that lasted maybe 30 seconds that required switching at around 3. The consequences for messing up the swap too early or not doing so usually involves taking more than double damage or flat out dying at a full stack debuff. Yes, the Warcraft Paladins were able to bubble off the debuff (Divine Shield) and right click it off immediately, but it was a 5 minute cooldown.

2. Increase the boss' auto attack damage

This can be a simpler solution to encourage more use of spells like Regen and Aspected Benefic to counter it. The occasional Sacred Soil -> Lustrate and Taurochole -> Druchole can work to help mitigate this if it is doing significant enough damage to worry about it.