They're too slow to keep up with modern battle groups. As beautiful and powerful as they are, they just can't keep up any more. They also consume massive amounts of fuel. I believe that it is correct to say that their time has come.
Personally, I would like to see them replaced with fully modern, fully armored, nuclear powered battleships. Nowadays, ships fight each other with cruise missles. I like the idea of a ship that just shrugs them off. Kind of like "hey, did you hear something" when a few exocets bounce off the hull.