One for Sorrow

So mere weeks before the release of DH I somehow have something to say about a storyline in HBP. It's two years late, but I need to pick every bone. I was reading stuff today about strong and weak characters, some of which I disagreed with, and unsurprisingly the Tonks storyline came up. I'm not really taking a position here on whether the story was good or bad for whatever reasons, but what I do think was that ( Tonks' storyline was useful. )