its a combination of things.
Stat sticks were op since the beginning. due to DW passive, and mainhand only skills.
The shaper mods, and %phys gained, or converted, took the OP statstick and made it completely broken.
Adding those shaper conversion/gained mods imho was one of the most bafflingly/short sighted things GGG has done. Power creep was already a big deal, and a huge complaint. then they added those things...
And they have also added, a great many more sources of flat added damage. Jewels, buffed added cold/icebite, steel rings, etc. flat added damage also, clearly benefits DW way more then 2h, and even more then 1h/s.
But the DW issue is also a large part of it.
10% more attack speed, 20% more attack physical damage, and 15% added block chance while DW. global.
This should be made to apply directly to skills, not as a global character buff. well, sure the block global.
But, it should be 10% more attack speed with attack skills that use mainhand, and offhand weapon. and same with the 20% more attack physical damage.
This way, mainhand only, attack skills do NOT benefit from the attackspeed and damage boost.
And while at it. 2h melee weapons should get their own innate buff. probably something like Ruthless.
100% inc stun duration, 10% chance to knockback, and 50% more attack physical damage on first hit, and every 3rd hit after.