That bleeds slightly into 2h melee, but 2h melee is better supported through skills. Any 2h gun build is better as a DW pistols build; and I believe it comes down to attack proc skills and the attack speed gap between DW and 2h, and for melee the attack speed gap between 1h and 2h. The extra firing speed of a DW gun build severely outstrips the damage potential of 2h gun builds because there aren’t modifiers on these skills for extra damage from 2h gun outside of the main hand damage modifier; but that’s often the least significant portion of the skill.
For melee builds, outside of Shaman, 2h modifiers for skills for extra power don’t exist as well. On the soldier side of things, there is Blade Arc, but Forcewave builds are more powerful with a sword and board than they are with a 2h melee weapon; you’re getting the same extra damage on the skill regardless of your weapon type. The same point about DW guns can be made for DW melee; higher attack speed = more procs = greater damage output. There isn’t much benefit to be had for foregoing a shield and using a 2h weapon for soldier.
I think the passive proc skills, like Reaping Strike/MarAdvantage/Bursting Rounds, need a 50% boost for 2h weapons baked into those skills. For the active skills, like Forcewave and Firestrike, the 2h modifier skills need to be added, and where they already exist they need to be buffed; especially for 2h ranged builds as that damage gap is bordering on unforgivable.
At least for piercing /physical builds. I can admit though that it could be my bad luck with 2h weapon drops… who knows.