Personally, owning basses with both configs, I can’t with any confidence attribute the differences between them to the fact the pickups are reversed or “normal”. There are just so many other variables. String gauge, string material, type of magnets in the pups, preamp, scale length...
Saying that, the logic behind reversing the P pups is pretty sound IMO - as I understand it, it’s supposed to help balance the tonality between the E/A & D/G strings. Trouble is, without being able to hear the pups both ways around on the same bass, all other things being equal, it’s nearly impossible to tell if I prefer them reversed or not.
3 out of my 4 P-type basses have the pups the “normal” way around and they all sound fantastic to my ears so I can’t say I’m particularly desirous of basses with the pups reversed.
Hölger Stonjek (the guy behind Sandberg basses) says that when he was experimenting with pickup configs and was working on the VM (P + MM) basses, apparently the P pup blended better with the MM pup when it was reversed. Without the luthiers resources someone like Hölger has, I simply wouldn’t know the difference!