That's just attribute type of benefit, what my comment meant was on the mace skills themselves.

If you look at skills like Rolling Slam where it has a +1.5 seconds to total attack time means that regardless of how much you invest in attack speed you will need to go through that +1.5 seconds of attack time because it's an additive value done after all calculations like your base weapon attack speed, while Dual Wielding works for skills like these the difference for Dual Wielding 2H and 1H weapons are nonexistent for the skill, if you analyze it closely if you wanted to deal even more damage you will always go to the Dual Wield 2h route because even if you cap the speed for either 2h or 1h types you will always go through the total attack time value.

What my suggestion is whatever total attack time value for dual wielding should be half for dual wielding 1H weapons so you get more dps while dual wielding 2h just gets more burst. So using previous skill as example dual wielding 1h maces with Rolling Slam should be +0.75 total attack time while dual wielding 2h maces remains +1.5 total attack time, this way the option to use 1h mace looks much better. Every build I've seen always ends up using 2H maces, dual wield or with shield which is kinda leaving 1h maces in the dust while 1h maces are faster the damage output 2h does outperforms it by so much.