I think, its better from now on, only hero and legend had the ability to give trust.
That's a horrible idea, and Theymos would never go for it anyway.
OP, those negs you got are not from DT members as far as I know--they're all showing up as untrusted feedback--so it's not like your reputation has been damaged. And for what it's worth, I don't think the recent Yobit campaign participants should have been tagged despite all the controversy around whether Yobit is truly a scam exchange or not. There isn't anything you can do about it, though. Most members receive BS feedback at some point, and nobody besides the person who left it is in any position to remove it.
That's how the trust system works. It's far from perfect, but it's not the end of the world if you get negged by a member who isn't on DT.