The front end looks more Taurus like and the roofline, particularly as it goes back, looks weak (for lack of a better word).
I understand the challenge of redesigning an iconic look. The current Mustang is unmistakable and connects directly back to its origins from the '60s to the early '70s. The Mustang II's of the mid '70s were horrible Pinto like cars and what followed wasn't much better although they did improve. The generation immediately preceding what we have now looked more like Toyotas.
This new look seems a bit too generic and Toyota like (to me), on the outside anyway. The inside seems fine.
Seems to me some of the other concepts or possibilities considered worked better visually than what they appeared to have decided on.Just google 2014 or 2015 Ford Mustang in images and you can see some variations.