
Mace skills too slow for levelling? Try 1 Handed Earthquake
With two tier 1 supports, from as early as level 4, we can get EQ's miserable 4 second delay down to 1.4s, which makes it perfectly viable as a 1 button clearing and bossing skill. The skill has no '+total to attack time' so using a faster 1 handed mace and taking skill speed on the tree is actually rewarding. As long as you keep hitting different spots of ground on rotation the time between ground patches detonating becomes the same as your attack time with the skill.
On another practice run I'm up to act 3 killing everything with just EQ and the occasional boneshatter with a 1 hander. As long as you keep your weapon upgraded (current league mechanic always helps a lot with this) it's smooth sailing. What's more, the 1 handed nodes on the passive tree even have increased attack speed, not reduced! Taking a handful of reduced skill effect duration on the tree also lowers the delay from 1.4s to 1s.
Don't dual wield though, it lowers your speed and your damage for some reason.