Gladiator is worse in the aoe and the raid utility department but im pretty sure it has stronger survivability than arms and fury with resolve (stronger Shield Barriers, stronger enraged reg), Shield wall, demo shout, last stand and then the fact that it uses tank stats to gain DPS makes it a lot more tankier by default.
I guess they could make demo shout make everyone in the raid take less damage and IDK buff bladestorm for AOE?