The funny thing about speed runs is people not understanding what they do. Like warriors rotating butchers block to hold enmity and using inner beast while at full life. And paladins circling like a chicken and not bothering to use flash. I don't know what do they expect to happen, bust is a fact - most of blms in df are afraid to use flare. I got a good habit of standing close to tank before i start healing so he can flash mobs away from me. Maybe it's some kind of reactive tanking - don't flash/overpower until you loose enmity. In the easier content bards can hold aoe enmity and tank very well (no joke) - let them tank and you should be fine.
But more often i get tanks who pull 2-3 groups and dps kill them 1 by 1 - because this (and many other weird things) is what people usually do in the duty finder.