Wat? This is EPIC CHANGE! Mastery will be very good for stacked fights and there will be talent which also trigger our mastery from proximity to Beacon. Our current mastery is just too powerful. New mastery gives us new interesting playstyle and there is no longer "herp-derp crit>mastery>haste cause because" - some fights will favor mastery, some do not. I like keeping two different sets on my char to switch between them when they're needed.
I'm only disappointed for no changes to Holy Light and Flash of Light. Still the same amount healed. It's boring. I'd like to see super strong and expensive Holy Light and super weak and cheap Flash of Light.