I don't know about flat out negative traits; they often feel one note and boring to me considering what we already have. However, I'd love more dominant and expressive traits which I think necessarily entail some to have negative effects. I am all for some trade offs if they are enticing enough.
That might have been the original goal, but they aren't powerful enough in general: positive or negative. Regardless, I welcome more options. I never used things like the hyrdophobe trait, but I remember 3 positively for giving me the option.
I do wish we could have something of a general coward trait, but I am not 100% how it would work without a fear emotion. Squeamish just isn't enough and it seems like an odd thing not to have.