Please explain why you are assuming this would help them more (did i miss something?).
They would just use alt accounts to leave lots of positive feedback to make themselves look trustworthy.
That's true, but
a) they can do it today as well
b) as long as they don't have an alt that's DT1/2 it's still untrusted.
Just to be clear: my main point is the visibility of untrusted feedback. I don't want to change anything on default trust or the difference of untrusted / trusted.
Edit: I think i will collect some of the scam accusations where this problem was a big factor and post them for reference.