NHL shooters have no problem hitting the uppermost part of the goal at will, and a goaltender on his knees simply doesn't cover enough of that area. This is a 6'5" goalie in that position (presumably having dropped down from upright after the shot is taken): https://www.1stohiobattery.com/columbus-blue-jackets-news/20...
If the shooter is 5 or more feet away, and has a couple seconds to set up a shot, and the goaltender is on his knees, it is virtually an automatic goal. Someone employing the strategy Dryden suggests should be the standard would lose every game for their team.
This takes away from his other very good commentary about the aesthetics of the game changing.