As others have mentioned, SMN is much more limited as far as movement then people think. SMN is having very noticable MP constraints in 2.4. In pretty much any one of the new fights a SMN using his/her optimal rotation (weaving in ruin II for GCDs and using miasma II with contagion), is going to result in the SMN becoming MP starved. Using ruin II during a dodge is going to drain you even faster. If your DoTs are falling off and you have to move, it is also going to result in a DPS loss.