True but those things on wow are more of a "clever use of game mechanics". That cryptic has put so much information client side is the problem. the only true dupe to exist in wow was back in vanilla when trade recieved was client side and you could bug the reporting by entering mara. after that they pulled pretty much…
not sure what these MASSIVE threat issues are, once you spec dps you dont have threat issues anymore, for each point of damage you recieve 1.25 points of threat. so unless you are doing 25% less damage than your dps threat isnt an issue. if you are doing that much less your arent doing it right or you are to undergeared.
you probably need to look at your overall dps output. as Gf you can be top 1-2 in your grp, going that way instead of debuff master will help more with threat on large grps of mobs. that or change your strat on fights like that. just have the DC kite the mobs with hep from CW and TR smoke bombs.