It does seem to mimic the 911, although that picture is a bit deceptive. I've seen some others that show the car from slightly different angles and that 911 similarity fades a bit. The similarity is still there, and no doubt that's what they wanted, but it fades.
On the other hand the soft top convertible reminds me of the 1960s MG, and I actually like that look better. Well, it's not an identical look to the MG, so much as it's just more simple and clean. Although that changes a little with the 2006 model, and even more so with the 2016, as the original style starts to take on a more "muscular" feel.
The retractable hard top with it's 911 look takes the Miata in an entirely new direction. It's almost like a different make and model. I think it will appeal to some people, although I still prefer the older look, myself.