Well, that’s a coincidence. Just this morning I pulled out a vintage Williams. And yes it was bloomed.
I have experimented with blooming and find that with some soaps, it speeds up the lather building process, with others it improves the lather all over, while with yet others it makes for too rich and dense a lather (or I should simply have loaded less) or no difference at all. Usually not so much full soaking as wetting the surface, though. A tablespoon or so works for me