I'm not a Saints season ticket holder but have been to many many games and have always at in different sections. The view has always been good from every seat. 643 was where we sat for the Cowboys game in 2012 and when you sit along the sidelines up top, the view is almost the same whether you're on the 50 yard line or the 10 yard line. The rows are pretty small though and I was jammed in with other neighboring fans but that made for great conversation. The circular angle of the sections also enhance the view from up top as well and the PA system is top notch. I could sit here again in 643 without complaint although I don't like how long it takes to reach the upper level from the bottom. Make sure you give yourself plenty of time to get through security and then maneuver through the crowds to get to your seats.
I'm definitely an advocate for playing football outdoors but the weather in New Orleans is so unpredictable and the Dome has brought a number of Super Bowls to New Orleans, so I'm fine with it. The only improvement I can think of would be to add cup holders to the seats and make the jumbotrons bigger to enhance the fan experience.