I could see Malkovich quirky enough to replace (at least partially) Petersen in Vegas. He has eccentricities galore in most of the characters he plays, including himself... 
Still, Petersen will be missed. He's definitely one of the reasons why I like the original CSI over CSI:Miami.
Cheers,
-CM-

Still, Petersen will be missed. He's definitely one of the reasons why I like the original CSI over CSI:Miami.
Cheers,
-CM-