Hum... I have a different view from this difficult ~ dps thing you guys are talking about, so just let me leave this here:

There are factors that are within the player's control that will lower or increase your dps depending on your choice, for example: a new SAM will often mess up and repeat their combos or let their kenki bar overcap, as he learns how to play the class these mistakes will happen less often and his performance will increase, which feels good; A BLM new to the Susano fight will often let his AF/UI fall or use an out of time transpose because he did not know the timers for movement moments, as he learns the fight, he will find ways to keep his buffs up minimizing dps loss by mechanics and his performance will increase, which also feels good.

But there are also factors that are beyond the player's control that will lower your dps and you can not do a thing about it, for example: Susanno will lock you up, Lakshimi will MC everyone during her long transition phase animation. Some classes are heavily punished by these things, like BLM who will see his buffs fall without being able to do a thing, and others will fell nothing but some downtime, and as long as the mechanic is over they are good to go, like RDM.

Now, since you talked about wow, I will do the same: Shadow priest has a talent called Surrender to Madness, in short this talent is a ridiculously strong buff that you can maintain for quite some time(but not forever), once this buff falls off you literally die(horribly) and can not receive a ress even if avaible. This is a perfect high risk = high reward situation, if mechanics and latency allows it this talent will turn you into the ultimate dps and you would feel like the guy bringing down the boss hp. But if mechanics would force you to stop attacking the boss, or run to the other side of the room where you would not be able to attack or some stuns/silences would be inevitable, in other words factors that you can not control, so the talent would end up backfiring and often you would prefer other talents over this so strong surrender to madness.

And I believe this was a good design, there is the difficulty that you can work around, and there is the inevitable punishment, for the first, I believe that classes that suffer heavily from the second should outperform in fights where the second is not a thing, as for the second, said classes should be outperformed by more flexible ones.