I can certainly think of an instance where presoaking might be beneficial - when prematurely "snatch"
processing to get the silver only marginally developed. In such cases the dev time tends to be very
short and it's difficult to do it evenly. I put the paper face down and rub it around very quickly to keep
any air bells from staying put, then quickly flip it over. Doing all that in half a minute or so is a bit tricky (thank goodness, I don't snatch develop very often any more, but "lith" printers might). And presoaking might help both with eveness of development and delay it a bit.