Looking over the class abilities I noticed the DOT stats vary, for example:

Touch of Death (Pugilist): Initial Potency 20, DOT Potency 25
Fracture (Marauder): Initial Potency 100, DOT Potency 20.

Both have a 30 second duration. Fracture does more initial damage, but which does more total damage? How often do Damage over Time abilities tic? If it's every second TOD does more, but if it's every 3 seconds Fracture wins out.