Aren't the many residents of suburban NO already living there??
I'm not sure. But there is a band of higher ground between the two rivers and a band of lower ground suitable for a canal running close to the existing Mississippi channel from the low ground along the Atchafalaya. That IMO is the logical place to build - because it's close enough to surviving NOLA infrastructure to where workers in the new town could commute to it but close enough to a possible Atchafalaya canal that the town would become the primary port once the canal was complete.