take it from the expert. *GASP!!*You don't know much about microprocessor design, I take it.
This is a huge redesign, with many parts taken from the bottom up. The Core was an iteration of Yonah, which dates back to the Pentium Pro design. This is a new design. I guess you didn't know it has a uop cache, similar to the Pentium 4. Or, uses physical registers files, again something the Pentium 4 had, but the Pentium Pro line did not. As you no doubt are unaware of, this entirely changes the architecture of the processor, since it fundamentally changes how instructions are tracked and scheduled in the processor.
The entire branch prediction is completely new. They now have one BTB to represent what was in the L1 and L2 of the Nehalem, and actually compress the data so it takes no more space.
To the uninformed, it might seem like just another iteration, to anyone who looks any deeper, it's been completely redesigned. It is fundamentally changed from the Nehalem/Pentium Pro line. The Core was the same basic architecture as the Pentium Pro, but with enhancements.