I vote hooey for the most part.
For how much a pickup swap costs, I've never personally experienced a swap where the difference was worth the price of it. Changing to a different string is a far higher bang/buck ratio in terms of altering the actual sound enough for anyone to really be able hear the difference. Going to flats from rounds or vice versa will make a huge difference for a fraction of the cost. Plucking in a different place will make an even larger difference for a cost of $0.00. A good compressor like a Cali76 will make an absolutely enormous difference for maybe around the same money. And so on.
In other words, unless you're chiseling new holes and putting completely different pickups in completely different positions in there, a pickup swap is a very low value modification in my experience. And what difference there really is is largely just placebo at that. Typically only audible to the player/owner, and not the audience. Worse, when you're done, you're left with the old pickups that you can't sell, because everyone else with your bass already has a set of them too that they can't get rid of either. Because they tried the same PU swap as you did.
In saying that, the bridge PU in my Tony Franklin is some kind of super hot deal that doesn't sound like any Jazz bass style single coil I've ever heard. It sounds like an extra hot overwound item, except for its puzzlingly good high frequency response which overwound pickups aren't known for. I've been tempted more than once to try to get hold of one somehow, and drop it in the bridge position of my Jaco. The Jaco has 60's style vintage PU's in it and it has always sounded, well, like a 1962 Jazz bass at the bridge. kind of weak and clicky cloppy, and very difficult to get consistent "pop" on the notes. Sounds amazing, with a nice, woody P bass tone on the neck PU, but just kind of clinky and watery at the bridge... Well, you can see what my mental process is on that... But so far I've known better not to do that because the result would likely be expensive and disappointing.
I am, however, more tempted to try putting rounds on it again and seeing what tonal changes that would make.
So I'm not totally immune to the idea, but I rarely consider it anymore these days, given the much higher value alternatives like new strings, better electronics and different playing techniques. The bang/buck is much more in favor of those instead.
L