Rebuild the port I say but not the city, those parts above water leave alone, blow the levees and let the river seek its natural points, keep the channels open and move the facilities that have to be moved twenty mile or more up river, I am sure Natchez or Vicksburg would like to become ports, then the Iowa can find its true home in davenport.
the other thing to do is build a canal from the gulf of mexico to the pacific and set up facilities for ocean going vessels along the canal.
Never let a hurricane knock out a major port without some sort of back up.