A few points to make:
In a very real way, Intel only makes two CPU products - the Atom based stuff at the very low power/low end, and then the mainstream line. There is only on basic "core" - sometimes there are 1,2, 4, 6 or even 8 cores (in some Xeons) and they vary the cache, turn hyper threading on or off, turn turbo boost on or off and thus generate a huge number of flavors, but at the base... there is only one core. Intel is really trying to stretch that one basic design maybe a bit too far?
You can design for speed or low power, but when opimizing speed paths it really is a very either or choice in cpus. Merom for the laptop line in the 2005 era s needed extraordinary measures to get much past 2.5 ghz, but when they opened up the power envelope and optimized for speed the C2Ds hit a bit under 4 ghz pretty much with ease...
We are (alledgedly) going to get 6 watt haswels, and maybe that is just too big a range to do with one basic design?
That being said, it could also just be early steppings as well.... Intel usually finds a couple hundred mhz between early production and late steppings as well... Remember the "E" stepping C2Ds