So I just hit 80....
It seems viable and I can try set up a build if you want.
I would probably recommend a combo, maybe Banner of Tactics, On My Mark and either Shake It Off for condi clear or For Great Justice for more might. It has reasonable potential for metric kitten-tonnes of might because of Blast Finishers (Adrenaline LB + LB 3 or Hammer Adrenaline) and then the FGJ for even more might. Admittedly I may not be the best resource for this, just feel free to ask me anything else. :V
Unfortunately in dungeons you only care about efficiency, faster killtimes = less time for enemies to kill you instaed: ideally you want your enemies to be dead by the time the guardian runs out of kitten -savers.
Hambow has low dps in pve, so while you certainly can run with that you most likely would be better off with something else. Axe mainhand and GS are the most effective weapons for a warrior to carry in a dungeon, you’ll occasionally need a ranged weapon to deal with a few specific encounters but the rifle is the preferred powerbased pve weapon of the two.