Also;
Port Authority seems to adopt this bird brain policy that one walkway has to be close any given time, even they post guards. If they open up the North walk way, I'm sure most people knows it has step on NJ and NYC side, but it will give a choice to some, specially busy summer days. What I like is that on NYC side from the North walk way, you are in the bike path in with in a few city blocks, versus almost 20 city blocks on south side of the GW Bridge. You are in traffic much less, that should count for a plus.