Well it's either characters' attack CD, or your clicking CD. At some point I noticed that my empowered clicks were charging up real fast, though it also could be a buff from goblin mage. I can try to upgrade attack CD further and see if my characters' CD is shorter. But man will that cost a lot of money, it already takes me around 5k currency to upgrade it further. I wish increasing lv. would also increase the amount of moni you would get from a stage, not just upgrade items