I played a build utilizing the Rotten Core node months ago (before the visual update to it made it a GPU eater) and had moderate success with it despite there being almost nothing in any of the mastery trees to improve it. I revisited it again because the passive trees have been updated since then and the Ice Thorn Totems node details that it converts the poison pools into an Ice Vortex, which scales with increased minion spell and cold damage.
Well, Shaman has decent sources of both, a good 100% increased minion cold/lightning as well as added minion spell lightning and a nice chunk of adaptive spell for minions.
The result is that even with an extra 100% increased cold/lightning damage and a 36% more multiplier from within the Thorn Totem specialization tree, the Ice Vortex deals less than half of the damage the default poison pool without those benefits.
Dropped the ice conversion in a heartbeat and saved myself 10 useless mastery passive points.
Please buff the Ice vortex’s damage. It’s sad and lonely.