The +power vs x stat, as it currently exists, is bloating the properties pool, and generally only serves one purpose: to help you hit specific damage breakpoints against specific mobs. Investing significantly into the stat specializes your build even further beyond weapon and class selection, in a game where you will constantly be facing all available enemy types with the exception of bosses.
To my knowledge, the stat currently performs two of the three functions of your base hero power: damage, and stagger. It does not affect your ability to deal damage to more enemies per swing.
To lessen the impact of this over-specialization, and provide new build options to players, I propose condensing the six properties (+power vs chaos, skaven, infantry, armoured, berserkers, and monsters) to three generic stats: +%damage, +%stagger, and +%cleave. I won’t suggest any numbers, I would leave that to someone with a better understanding of the game than I have.
I believe these three stats would better allow players to meaningfully customize the effectiveness of their weapons, to either exaggerate a weapon’s effectiveness at its intended role, or to round it out to better deal with the variety of enemy types and numbers the game throws at you.