Are role actions a nerf?

[Kaisinel]

Most dungeons esuna can be used to cleanse usually avoidable debuffs

Most trials, you don't need esuna.

Most 8 man raids, you don't need esuna.

Most 24 man raids, you don't need esuna

This should give you a general idea what places Esuna is applicable. Usually Esunable debuffs are avoidable

Also, with 4.0, you can see what debuffs can be Esunable now, instead of it being a guessing game.
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There are only a few instances in which Esuna is required, those are generally for insta kill debuffs such as A3s and Doom.

Esuna is generally a dead skill.