Originally Posted by
ty_taurus
If you've not played FFXII, that icon flickers slowly and cycles through each debuff on your party members. You also see an icon near the health bar above their head, and the name of the debuff pops up on the character who receives it when its applied, not to mention most debuffs have a visual effect on your character. Poison turns you purple, slow turns your character's shadow red, oil turns your character mostly ink black, etc. Some combination of these elements could also go a long way at communicating what can be Esuna'd vs what can't, like a Vuln up.
As for Paralysis, I always Esuna it off BLM first, as well as SAM, SMN, and RDM since it can interrupt cast times, and for BLM that can be devastating potentially since it ruins your rotation timing, and with their long cast times, it's very likely to occur. Other jobs, I don't always remove it because it's not really a problem for MNK or DNC. It can techncially interrupt them but it isn't likely too and they have mobility to get out of AoEs. But it depends on the situation. If it's a single target Paralysis, then usually I'll do it regardless, but if the party is paralyzed, like in Puppet's Bunker, by the time I get to other jobs, it's probably not worth casting Esuna since the timer will be running out anyway.