Enmity. Aggro. Threat. Whatever you want to call it, there are times that that thing may reset in a fight and it's up to everyone to make sure that the next attacks (which often include a tankbuster rather early) hit the tank and not a poor, unsuspecting DPS or healer.
Today I died to two of these situations, once in o5n which I got for Normal Raid Roulette and again in Ridorana. Each time Diversion and Lucid Dreaming were on cooldown.
For those who don't know after you leave your respective ghosts on Doom Train and after Construct 7's add phase the threat on the boss resets. A lot of times when a boss spends a significant amount of time away from the party this can happen. I'm not sure if it's intentional on SE's part (it likely is) or if it's a side effect of the party being away from the boss for so long.
No matter the cause it's a thing that happens and as someone who plays a bursty DPS job (RDM) and the healer that generates the most enmity (WHM) this is something of a concern for me.
I underatand things happen. Tanks die, other tanks don't pick up the boss right away - in those situations it might be frustrating but I can understand eating a few auto attacks. When there is a predetermined threat reset though? No, this just isn't acceptable. Despite my healers best efforts Divine Bension just isn't enough to save a RDM getting hit by Destroy.
So dps - be aware of these times and save enmity CDs for them when possible. I tried, and had Diversion pocketed on Construct 7, but in the add phase right before that my tank wouldn't leave Deliversance (despite not popping IR) so I had to use it there. On Doom Train I had Lucid but it didn't dump enough as I was doing a melee combo and Verholy pulled threat right back. Thanks Crit/DH melds.
Tanks - this is ultimately on you. A tank geared enough to enter Ridorana should be able to hold off of a RDM in 360 gear, you just might have to use tank stance and/or an aggro combo. I promise the dps loss of my death is more than you briefly losing 20% ,especially on Construct 7 where not only do I get weakness but I lose the 2 stacks of Damage Up from the previous Computation Mode.
Do your job. It is to tank the enemies. Provoke is on a short CD. There is no reason for this.
Thanks for reading my rant. I hope it saves a few thousand MP that would otherwise be spent on needless raises.