I wondered the same thing a few days ago. I haven't reported anyone really at all in D2.. either way (good or bad). I was doing a strike where a dude was basically AFK the whole time. I reported him as such. It was annoying. However, I was thankful to the other guardian who kept with it and we two-manned the whole thing. He was decent skill-wise too. I was going to report him as helpful and skillful, but then realized it wasn't an option anymore. Seems silly to remove it, while simultaneously adding a bunch more options on the negative side. My guess is that only a handful of us actually ever rated people in a positive way.