Questions about slot and slotless motors

I was told a slot motor has larger torque than a slotless motor and hence slot motor has lower kv than slotless motor in the same condition.
A iron core in a slot motor not only acts as a magnet filed amplifier but also a large heat capacitor which can lessen temperture increase.
Both solt and slotless motors exist in the RC market.I think they may some com
plementary pros and cons. Manufactures should have some reasons to use solt or slotless motor.