New HV Sintered Tuning Rotor with 5mm Shaft Question

I noticed on Novak's website they are advertising a new rotor for the HV motors.

"Description

This is Novak’s HV Sintered Tuning Rotor with 5mm Shaft – 14mm (#5951). The 14mm rotor’s larger diameter and improved magnetic material provide a higher temperature threshold, enhancing its durability. Its higher magnetic field also increases the motor’s natural drag braking and improves its acceleration response.
The HV Tuning Rotor is compatible with Novak’s HV Brushless Motors with 5mm Shaft (#3524-#3527) and Novak’s original HV Brushless Motors (#3424 & #3426) with an upgraded 5mm Lightweight Front End Bell and Bearing Kit (#5917).

To take advantage of the lower Kv generated by the HV Sintered Tuning Rotor, Novak offers four 5mm Mod 1 Steel Pinion Gears 17T-20T (#5111-#5114) that are compatible with the 14mm rotor.

Expected Ship Date: End of May 2009"

In general I am sorta a newb with motors, so can someone (NovakTwo?) explain to me why I might (or might not) be interested in this?
Is the only improvement the drag break and acceleration? I know with their previous rotor improvement it increased the wattage of the motors, will this rotor effect that? Am I properly understanding that it will help the motor run hotter (without failing)?
Explain it to me as if I were slow... (because with motor stuff I am).

Thanks