Mix of general users lack of understanding about computers mixed with the advertising from MS showing this as a do-all machine. Entirely un-surprised about it, been this way for quite some time with various laptop releases and such, and even the IPAD which people buy thinking it will be an actual computer then realizing it is basically just a media consumption device.
The SP3 is a great machine, be it i5 or i7, and will be very fast assuming your not doing tasks on it better suited towards workstation requirements (rendering, extended calculations, gaming). Other than gaming, 99% of regular users would never experience a time when they are maxing the CPU out for a extended period of time to experience the throttling. Benchmarks are showing an artificially bad review of the device by putting it in the worst case scenario (as a benchmark is designed to do) to test the hardware. Im not defending MS here for not having a cooling solution/device design that can cope with extended sustained 100% workload, but at the same time, this is not a realistic scenario for the user-base. Just keep this in mind here when considering the negatives that people bring up.