Got asked this elsewhere but thought it sat best here... and I’m sure others will want to chip in...
Quality wise... not much at all... I know some who would say that Paul’s basses are a smidge better! Shock horror! Paul’s very keen to preserve the Walness of Wal so any changes will be subtle tweaks. He’s probably a bit less open to wacky variations than Pete and Ian were but I’ve seen solid body basses that he’s done, for example. I understand that he doesn’t like maple fingerboards and won’t do them. But I have seen some with additional inlay etc.
Given the hand build nature of Wals there was always subtle variations and departures from the norm with Ian and Pete... viz the transition Pro/Customs with coachlining, subtle headstock shape differences etc.
Paul does take a lot of care with wood choice. Good quality shedua is getting hard to fed so Paul has made it an upcharge wood and made zebrano a standard wood. However, that means that any new shedua basses tends to be a bit spectacular since, If Paul’s going to offer it and ask extra money for it he’s going to choose the best examples. He’s also looking at weights of wood . Back in the 70s and 80s when men were real men, women were real women and small furry creatures from Alpha Centauri were real small furry creatures from Alpha Centauri weight wasn’t such a big thing. I tried a Mk 3 a year or so ago that he’d made so light I almost threw it through the roof when I lifted it off the stand. Still sounded full and fat but he’d clearly chosen the woods carefully for weight and resonance. Just to show that a great Wal doesn’t have to be a boat anchor.
Basically, in my view any cachet from an Ian/Pete Wal is purely romantic feeling and nostalgia. Paul makes great basses. Every bit as good,
And who taught him his trade? Ian and Pete!