I'd prefer year-to-year, but...considering he may only be playing one year anyway if the CBA goes south, I can live with this. It's cheap, it's short, and he's not terrible, so it can't be all that bad of a mistake.
Are there significantly better options for depth defensemen out there? Probably not. We'll be pretty banged up on defense even starting the year - Chara, Miller, Grzelcyk, and Moore all ended the season injured, off the top of my head, with McAvoy and (ironically) Carlo being relatively unscathed, I think. Even if they have the (abbreviated) summer to heal, that's a lot of bruised defensemen, and Kampfer didn't really make me want to throw my remote at the TV too often.