Kentsfield is going to be released as an Extreme Edition part which means that its targetted at enthousiasts. Your average joe wouldn't know what to do with 4 cores anyways (although even enthousiasts might find it a bit hard), and the average joe wouldn't want to be spending $999 on a CPU anyways. Being an Extreme Edition the target Intel board is the i975X which is exactly what the case has been for all the previous Extreme Editions (namely the 955EE, the 965EE, the X6800, and the X6900). The RD600 is supposed to ship with 1333MHz FSB support and the nForce 590 is supposed to have a Q4 refresh with 1333MHz FSB support. The only one lagging behind is the i975X, although it actually has a 1333MHz option in the BIOS. The support for a 1333MHz FSB among the targetted Extreme Edition boards is there, it's just whether Intel decides to take advantage of it.
None of this excuses Cloverton for being on a 1066MHz FSB though. I can understand a 1333MHz FSB on servers might create some concerns in terms of stability, but tightening up the quality control and binning a bit, take the time to validate properly, and there shouldn't be a problem. Intel still has more than 6 months, so they should be able to figure this out.