I adjust my tanking style to fit the group I am in based on a quick look at their gear and their performance in the first pull. However, it is true that most people expect tanks in 50 and 60 dungeons to pull big... sometimes excessively so. It is also true your typical random DPSer in DF is terrible and does a mere fraction of the damage output they could do which makes those big pulls more strenuous on the tank and healer <_<
Personally I prefer a smooth run over a fast run. They can certainly be both but if I decide to pug into DF I have no problem doing small pulls if that is all the group can handle.