Personally, I love the hard-hitting style that a lot of 2-H weapons feel like they should bring, but the numbers just aren't there. It's a shame that dual wielding offers more mobility, defenses, and more damage than 2-handers. While I know that a large portion of the playerbase prefers to attack fast, please consider the fact that many players are choosing not to use 2-handers because they are simply worse rather than because they lack the flavor the players desire.
Mace can have stun related, Staves can get block/chance for extra attack (for the kung-fu feel, and you KNOW melee staff needs love), Axes can get raw power/bleed, and Swords could be crit/crit multi.
Throw in some Uniques to completely change up the game as far as how the damage is delivered, damage conversion (hello strap that turns 2H into Varunastra ), maybe some whacky stuff with weapon range and you've solved a problem and added new play options all in one go.
A lot of these things could be systematically addressed if GGG were so inclined.
Add a 15-20% More Damage effectiveness multiplier for all melee skills when using a 2h weapon.
25% intrinsic AoE increase when using a 2h weapon.
Increase the melee damage bonus of Str from 2% per 10 points to 3% when using 2h weapon.
Add a 7th affix slot to rare 2h melee weapons that can be either a Prefix or a Suffix.
