Adding attack-or-take-damage/die mechanics to end-game dungeons

[BaconBits]

What are jobs that have to work around cast timers supposed to do in this proposed content? Run around doing nothing but spamming their instant cast DoT (or I suppose Scathe for BLM) to avoid damage until some more useful instant cast comes off cooldown?

Sighs in Reprisal spam.

Laughs in Stockpiled Xenoglossys, Triplecasts, Swiftcast, Umbral Paradox and Sharpcast procs.

Guffaws in Summoner.