well without knowing the pickups being swapped its hard to say what the tonal effect will be. sure, neck pickups are generally wound different to the bridge models... but within the BKP range there are neck humbuckers ranging from 7-17k, and the bridges range from 7 - 21k, and they use very similar winding techniques, magnets and construction.
Thats a lot of cross over between the available bridge & neck models and absolutely no basic construction reason they cant be swapped
...
apart from pole piece spacing ;)
I agree it is mainly (though not totally) aesthetic - but I have put wide spaced bridge pickups in the neck position before and was not happy with how it looked, i also felt the string balance was off from the dodgy alignment - but reckon that could be sorted with pole piece adjustments