Currently I'm only 33 and sunder doesn't seem to be doing all that much threat which makes me wonder if the lower ranks are generating any at all properly. Like I know that sunder does statis 261 threat at 60 and I'm not sure what it's supposed to be doing at my current level, but for now it doesn't seem to be doing any threat at all
While refining some 230 ore I managed to find this: https://wow.gamepedia.com/Talk:Sunder_Armor
Specificly the : "Threat scaling through ranks." section is what I'm interesting in, if it works as said in the link I'm wondering if it is working like that here on warmane.