I have less of a problem with DefaultTrust right now however than I do with trust ratings being used for disagreements and petty things. There are a few people on DT1/2 who use negative trust against people just because they spouted some opinions they didn't like, and pad their reasoning with some words about how "this makes them untrustworthy". It's very blatant mis-use of the system IMO.
Whatever trust system is in place this will always be the down fall of it. Trust and petty disputes go hand in hand and will the trust system will always be misused. The only solution I see to this is a trust system is not accepted until its been approved by a majority of people. So if you were to put a trust rating on me "This dude is cool" then similar to how flags work members could either support it or oppose it for being a good reason to leave trust. If the majority of people oppose it then it would go under untrusted feedback and if enough members support it will go in the trusted feedback. The support/oppose weighting would be relative where that member is in the DefaultTrust list. So DT1 would be higher weighting than that of DT3