Essentially, gladiator has a lot more mitigation compared to marauders, who rely on a bigger hp pool. Marauders however have much better area enmity generation attacks. You can mouseover the skills on your class ability page to see which skills you need. There should be a list for effects on the bottom of the mouseover saying increased enmity. Those are your abilities that increase enmity. And marauders use Overpower, a cone area-of-effect attack that generates enemity instead of Flash. You can use flash also as a marauder, but it's not your go-to skill for area enmity because of your mp.