It's too similar to the outdated outgoing model. There is, in my opinion, nothing that screams, shouts or even speaks loudly, "hey look at me". It now looks like every other generic coupe out there. Fords over-use of their apparently new trademark grille/front end design on every model dilutes the "newness" of the Mustangs design. Of course with the flood of performance enhanced versions Ford will undoubtedly release to boost sales we will get all kinds of 80"s GM gaudy aftermarket decals, scoops and wings stuck on it.
In the scope of new auto design, the New Mustang already looks dated.