I think you get the wrong idea about mace.
Mace is the oldest weapon type in the world.
To deal enough damage, It need to be heavy because off the equation [Power = Mass x Speed] , the light one is need a lot of speed to deal the same damage as heavy one.
As Impact-type weapon, It isn't effective against armored target because the damage it causes will be absorbed by armor except impact force is higher than armor can absorb. (there is 3 type of physical attack, pierce(point of impact), slash(line of impact) and crash(area of impact). some armor can protect some type better than other.)
It also need full swing to use it effectively.
My weapon of choice is katana. The best sword in the history.