Yes, making the presense of downvotes easier to notice and thus increasing the frequency of whines about downvotes would suck. The remaining code isn't hard to implement (most of the harder parts were done quite a while ago -- I think the updating of old nodes still needs to be done, and I'll do that after the new node cache is put into production).

A tricky part is designing how/when to present the information to provide some benefit while avoiding most of the potential problems (as I discussed in more detail previously).