[GriffinRU]

I think you referring to different type of motor...
The only advantage of making rotor from sections is to get stronger magnetic field (in comparison with single one) and make it more uniform in production and probably uniformity of the magnetic field as well. To obtain higher torque you need to create more poles or add core but by doing that you sacrifice speed in first case and efficiency in the second one. Different wiring schemes are focused on reducing motor inductance and resistance, as well as heat dissipation (air is bad heat conductor, so special epoxies and winding pressing helps).
Also you can destroy magnets by applying high currents (especially when it is cold... well, different story) but in this case segmented magnet will be more tolerant to that situation.

Slots are great for stepper motors not for servo...

Artur