Do increased windings conflict with thicker coil diameter?

[ChineseSmeagol]

I have read that to increase motor magnetism that an increase in the windings increases the number of tiny magnets that can be used to provide the magnetic force. I have also read that increasing the cross section of the rotor increases the efficiency. Finally I have read that increasing the coil diameter of the wire used for winding increases the efficiency of the motor.

These sound somewhat conflicting to me. If one increases the number of windings but also chooses to make the motor larger and the coil thicker isn't the magnetism decreased because of A) increased resistance to the current because more windings creates a longer path, B) a larger cross section reduces the magnetic aggregation, and C) the coil diameter of the wire makes the motor a lot more heavier and thus more initial load losses?

 

[mfb]

A) increased resistance to the current because more windings creates a longer path

You have an increased resistance but you need a smaller current for the same magnetic field (and even smaller for the same product of magnetic field and area),

C) the coil diameter of the wire makes the motor a lot more heavier and thus more initial load losses?

That is true. If you want to change the speed frequently, a smaller motor is better.