Look, people: ragging on singers for being flat who otherwise give great performances is just lame. Are you Sondra Radvanovsky's rehearsal pianist? Do you have to sit next to her at choir? No. Then I guarantee whatever minor, subjective flatness you're hearing is not that big a deal to you. Obviously, I'm not saying that noone has pitch problems, but there's a difference between pitch problems that are obvious and pitch problems that only you and a handful of other people with magic bat ears like yours can distinguish. Pointing out the former is fair game, but one should think long and hard about how maybe so-and-so's voice just sounds like that before going to press with the latter.