should a bmx hub be stiff?
 

I just got my first bmx bike, and coming from the road bike world, the hub is pretty stiff, and does not spin as effortly as it would on a road bike.

I don't know if that is a desireable trait for bmx riding or if maybe if I should adjust mine.

If you flip it over and spin the cranks, the rear wheel will stop fairly quickly compared to all my other bikes that spin quite effortlessly

No it should spin just as freely as a Road Bike hub. Some BMX's use loose/caged ball bearings, and the grease can dry up over time. So you might need to take them apart and either clean or replace the ball bearings.