Chieften Endurance charge gen. Question

I was wondering why was the 20% chance to gain endurance charge on killing burning enemies removed? And seems to be replaced with 35% chance when using fire skill.

I think it is a shame that Jug is looking ever more great for even Cyclone CWC BV using Ngamahu axe to get 100% phys to fire, Kind of feels like you gutted this one thing on purpose and would realy like to know why.