I disagree in a few key areas.
Life per hit isn't terrible on an amulet, until you find something better I'd reroll Vit to Crit or Crit Damage.
Wrists, reroll Resist All to Fire %. Don't touch the Vitality!!!!
Legs I would have rerolled the Life Regen to something else (unless it rolled a skill). Really, you should get better legs. Dex/Vit/Resist All are ideal.
Shoulders- get rid of the companion damage for CDR. The only damage skill worth getting on your gear is Multishot, and even that's only on boots. RCR isn't worth gearing for- that's why you wear Yang's. IAS isn't a huge priority. Dex/Vit/CDR/Area Damage is ideal. Bonus if you get an elemental resist secondary.
Hands- Dex/Crit/Crit Damage/Vit is ideal unless you really need more CDR.
Focus: Reroll Resist all to Crit or Crit damage.
Restraint: Reroll IAS to Crit or Crit damage.
Belt: find a Witching Hour. In the meantime, reroll Evasive Fire to Life %.
Chest: Reroll Sentry Damage to Vit. Ideally, you want a chest with Dex/Vit/Reduced Elite Damage.
Helm: Reroll Mutishot damage to Crit
Your Dead Man's Legacy is pretty bad. Ideally you want Discipline, CDR, and Crit (you're 1/3)- and your multishot damage and threshold rolls are near minimum.
Your Yang's is also pretty bad. Minimum discipline, low attack roll, near-minimum resource cost reduction roll... I sincerely hope you've got more Gifts, I would have rerolled Vit to socket and used it until I got a better one, or reforged it at the earliest opportunity. The Dex, Vit, and % Damage rolls are pretty good at least.
Vengeance: Run Seethe.
With the right gear, UE can totally solo-push GRs into the 80s or higher. Your gear is missing a LOT of Crit and Crit damage. The RNG is trolling you with the rolls on your weapons.
With that said, you've got the actual build in place, so if you reforge your gear I think you should be able to clear GR 55 pretty handily, especially if you run CoE.