From the Redit Q&A: "Broadly, we've tried to define areas in which specializations should excel (single-target, cleave, AoE, spread, clumped, burst, sustained, etc.), and areas where they should lag behind."

What frustrates me is how half of those situations no longer exist. I think it is a good philosophy in a vacuum, but has remained rigid while the game has adapted around it. Long gone are the days of Elite mobs being a thing around dungeons. Where 3 and 5 person quests were actually no joke.