Should I ditch my mage?

Most of the jobs in 3rd/4th that aren't "omg one skill that does over 90000000 damage" type jobs, such as shadowers, mages (until they get maxed ult's, and that's not too usefull for bossing anyway), buccanneers, etc, usually are VERY underrated. They aren't as weak as you'd expect. They just need to know how to be played, for instance combos, different skills, etc.
Really, it's more about the player.
Sure, a dexless night lord could outdamage a mage, but where's the fun in that? If I wanted to spam the same button all day long I'd go play runescape.