Q:
WvW DH backline sniper/support build?
Not really since longbow has been nerfed (True shot, Hunter’s ward) and there is so much projectile hate. If you’re looking at ranged only you need to run scepter ( + shield/focus) or staff as a swap. Neither are amazing damagewise.
In your backline: Elementalist+Mesmer+Necromancer
Go condi (dire armor and balthazar runes). Staff, scepter and torch.
Then just drop symbols and purging in middle of enemy zerg.
Kills 5 or more almost every time.
Scept/Torch for DPS, some support depending on build aka Honor for heal/large symbol. And Staff for the support only. I mean peeps still use LB; but not the way you want. Note: Scepter REALLY is a midrange and even close range weap; do NOT expect to be at LB range using scepter and be as effective, it’s not a snipe you’re looking for esp with torch that is not long range. Focus then be better if you want to be effective at the longest range which again, is a bit less than LB/Staff range.