I find that a lot of NA (1st gen) Miata people are insanely partial to the styling of the NA and don't really like the NB. I tend more to think that the NA looks alright but nothing special, and is a little cutesy and boring, but can be buffed up with a bit of work; whereas the NB is nice and curvy and more like a Japanese mini version of a Jaguar E-type than the NA's Japanese (i.e. not gonna break all the damn time) version of Lotus Elan.
But it makes sense for Mazda to go back to some styling cues from the NA. Since Miatas tend to be 2nd cars for lots of people, they are typically owned by the same person for a longer amount of time. Even the newest '97 NAs are getting pretty old while the oldest of the '99 NBs (mine's a late build '99 with low mileage, and I just bought it 7 mos ago anyway) are still reasonably fresh. So the people who bought NAs when new as second cars are more likely to trade up to an NC. People with NBs are less likely to be in a position to buy another Miata just yet.
But hey, I like all Miatas.
And rich, maybe when the NCs start showing up on dealer lots you could get rid of the MR2 and pick up an old but low mileage NA from someone who just bought an NC.