Ability to include someone in your trust list as "Ratings Only"
I've thought of this option, and I do think it can be helpful. It would be nice if we could add a custom depth to each of inclusions, but like o_e_l_e_o mentioned, it would add complexity to an already complex system.
You can add users to an alt account, then add that alt account to your Trust list. This way, you trust them one level less deep.
I haven't used this option yet though.
I agree the current trust system is complicated enough already, if not too complicated. Promoting custom Trust lists is more important now. I've suggested a big banner like the April Fool joke before, that had a lot of response in just one day.