Well, if it is supposed to be thicker then I suppose I have a mildly unique pickup lol. But in all seriousness I greatly enjoy my guitar's voice right now. But back to the magnets, I know that Mojotone sells thicker ceramics (they use them in a few of their own pickups).
yeah, magnet thickness seems to have less influence on voicing than wire gauge, insulation or overwinding, but it does make a difference on output and low end response
I once asked for an overwound riff raff (when BKP still took custom orders), and Tim recommended a thicker alnico 5 bar instead, and that's still my favorite pickup after a decade, but I can't hear much of a difference from a regular riff raff, since the supposedly larger field and thicker low end might be compensated by pickup height setting (I believe)
I also came from the SD magnet swap crew when I first started with BKPs
tried an alnico 8 bar in a holy diver, but I much preferred the original a5, although it did transform the pickup into a fire breathing beast (regular hd has a medium output)