I'm not expert in Star Wars nor in fencing. However, I think there is something not very logical in the way Jedi and Sith use their lightsabers.
I've always thought a proficient lightsaber user would not use robes nor cloaks in order to avoid being disturbed by large pieces of cloth. Some fencers used to have a "fencing cape" some centuries ago which added style and might help disguise the gestures made by the fencer, but these were to be maximum 80 - 90 cm long and not to weigh more than 1 - 1.5 kg.
Maybe I'm wrong, but in medieval times for instance, capes were to protect the owner (from cold, etc.), but I don't think they would use it on a battle field.
I understand there must be a "style reason" behind this, but aren't Jedi's Robe or Sith's cloaks a disturbance while fighting ? Isn't there useless weight added which would slow down their movements?
I don't see why they would not wear minimal gear to enhance their speed and freedom of movement since there is no real protection to a lightsaber hit.