It is what jajaja does in his build. If you crit upheaval and blind fury procs. That’s all. Problem with Zollhan’s is that it interferes with Upheaval which is why he sticks to Feral hunger alone and he talks about it.
If you haven’t reached blind fury yet then of course you have doubts:). Try it on upheval, it’s a massive adavantage. There aren’t many ways to boast two devotion procs on autoattack skills. WPS like Zollhan’s are unreliable in doing this. It’s a chance to proc on a chance to proc skill. So if you have Zollhan’s at 25% and crit chance at 25% your actual chance to proc Blind fury or AM is actually just over 6% agaisnt single targets. That is pretty bad. not to mention you need to invest more skill points to get ZT at 25% while Upheval needs only 1 point
Chance on Upheval is same as your crit chance. If you have 25% crit change then you have 25% chance to do Upheval and automatically proc Blind fury