Some jobs aren’t well-balanced in dungeons

[Semirhage]

Another thing to consider is that dungeons are casual content, and many people play them (very, extremely) casually—it's hard to get an accurate gauge of where jobs stand.

I'm going to make a very bold prediction: like savage raids, the savage dungeon will be clearable with all jobs.

Clearable, probably.

You're basically griefing unless you run WAR/SGE/BLM/(probably)SMN, also likely. The sustain and AOE damage of that combo of four is significantly better than their competition.