I will simply say if we can create the system  that DT feedback will be applicable only if it supported by 2 other DTs.

In this case at least we can stop/minimize the abuse in which people are tagged for saying "lemon".  I guess 3 people will not be having hatred for lemon simultaneously.

Same goes  for +ve feedback too, where people get +ve for doing a $10-20 trade, at least  you need to be trusted by at least by 3 people to get the +ve rating.

Since many of the DTs are inactive, we need to expand this network but at same time it need to be make sure that a single DT rating should not impact an individual.