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.
This would give even more power to this DT structure.
Maybe, but if a DT feedback's pattern becomes too evident (like several dubious rates applied by a same DT minor group), it will be easier to spot who is acting in cartel, the exposure is higher than supporting partner DT's feedbacks only with words. Higher exposure is good, because it's harder to be omitted and trivialized.
Anyway, even with high exposure, if no one complains and express their opinion, nothing will be done and the abuses will continue.
It's not a definitive solution, but an improvement...