It's not meaningless, who Roberts is replacing. This is Chief Justice stuff.
I still say that he is replacing O'Conner's seat and Renquist's role.
What I mean is that I don't believe in quotoas, i.e. replacing a lib with a lib, or a woman with a woman, or a Black with a Black. I believe they are not replacing anyone, they are joining because they are the Presidents choice, period.