Now, a 200Mhz bump with some new 6-core processor with additional cache may improve things more than you'd think...but its not necessary right now. The 2.3 i7 quad is plenty quick and blows away its predecessors. It would be nice also see a move to smaller-cooler manufacturing. While the performance difference between the 2.3Ghz quad in my laptop and the 6-core Xeon in my desktop is surprisingly small the noise difference is noticable. When something does get the CPU roused up it sounds like a jet turbine, albeit, a kind of neat-sounding turbine. Fortunately, you don't hear that very often, only when all 4 cores are stressed for some time. The Xeon can be running full-tilt and it always sounds the same.
If a 200Mhz bump could accomplish these things it would be worth looking into...but not for me. I'm done a good while.
Of course it would be different if it would also add cache and it would be on the hexa-core... but that wasn't a part of the deal, was it?
2.3 i7 is enough; even 1.7 i7 on G73 is damn fast and is enough for whatever you can do on a laptop, even gaming.
Don't compare i7 to Xeon - Xeon is a workstation/server CPU and as such is made to remain as stable temp-wise as possible, I think. You don't want temperature jumps on the server