Like it or not, I think there are two ways of looking at the XLR.
Either it's a tarted-up, de-tuned Corvette, or it's a Corvette being taken to the "next level" of sophistication made possible by the higher price-point.
Only time will tell which is correct.
I think a dressed-up Vette is an awesome proposition. "Nothing more than?" It's stiff, it's large, it's light, and it handles like a TYCO CurveHugger II. I don't think "more" is possible.
XLR's dressing-up is significant, addressing all of the things that keep Corvette out of luxury-roadster territory: DOHC engine, five-speed auto, comfort-tuned suspension, luxurious interior, power hardtop.