Making the retro ND would be glorifying the success of what they've produced in the past rather than looking forwards and focusing on the now. "Retro" builds are awesome, but it's only the NA that can excecute it, you wouldn't get away with spraying an ND with British Racing Green paint from the 90's....
The NA was made to tip its hat at old British Roadsters from the 60's. By the time they were designing the NB it earned the right to be referred to as its own vehicle....
Each model should be distinguishable from another, they should look as if they've tried to improve on everything from the last. They stay safe by sticking to their design of it being a minimalist car. Replicating the miata isn't difficult - it's difficult to do properly....
It was a ballsy move making the new model look as modern as it is, but we live in a world with smartphones and WiFi now, not tape decks and waiting for dial up
I think they did the MX5 justice.