As I said above, because of the noise regs we need to get the RPM's down. you can do this with several factors : the prop dia' or pitch. The number of blades and the wide of the blade.
Because of the ground clearence, most have tended to go the pitch route. But recently due to electric, the newer tallbody designs and the availability of longer UC's many have also experimented with a larger dia' less pitch props to get the same effect.
What people have noticed is that because we tend to fly quite a long way out, using those low pitch props at our low RPM can cause the airplane to appear to be flying to slowly!
It just take to long to cover the same distance. Thus some have gone back to the higher pitch selection. Mind you we're not talking much here, for example: Those using a 17x12 may today be using a 18x10 and flying slightly slower and slightly closer than the did in the passed.