I suppose the line has to be drawn somewhere or else you'll get inconsistent enforcement. Just how far off the line will be too far? So the one foot on the line rule makes sense. It'll be interesting if this rule does start getting enforced now in the men's game. The rule has always existed but almost never enforced and goalkeepers have been edging further and further off their line over the years to the point of becoming ridiculous at times. There will be initial chaos if it does happen but in the interest of fairness I think it'll be a good thing once it settles down and keepers get used to it.