Dungeon Warrior using Shield?
Meta builds use all off hands, but shield is the 2nd least used( along with axe). It has some situational uses like skipping in arah or blocking long channeled skills ( alphard).
Reflecting certain mobs, or swarms of mobs, can be fun. Try the shield recharge+reflect on block traits.
Typically you won’t want to use shield in a dungeon because it’s a defensively oriented weapon. It can perhaps be handy in situations where need to run past mobs since you can block a lot of their stuff, or if the boss has a certain attack that you just can’t seem to dodge.
The only two traits that are really relevant for shield are the shield master and missile deflection traits, which are both in the defense line (also not really used for dungeons). Distracting strikes in strength is another possibility since the shield has an interrupt on it, but the way defiant works prevents it from really being that useful on dungeon bosses.
Any situations where you need projectile reflection/blocking is generally handled by mesmers and guardians, and the warrior is much less effective at it anyways.