The discussion is pointless since we already know what the deal is: Christina sounds good, very good, in certain registers, but sounds awful (although with much power) when belting. It has always been like that and her voice has never been one of those which have it all. Of course it got worse over the years, during the relese of Bionic she still was sounding like she always used to. It was after Bionic when she really started to sound worse. She still is better as an artist than many and her albums can always be interesting, unlike a Britney for example. But it is a fact she doesn´t have anything on people like Mariah and the likes. For so many reasons.