Overall, I think it's a huge improvement on the current 'stang, particularly the front end. I'm not a huge fan of the whole retro design movement, but I have always thought the current model's nose was hideous _ huge gaps everywhere, lights that look like the fake headlight decals they put on NASCAR racers, etc. For me, the thrown-together front end (along with the fake scoops) was always a deal-breaker on what is otherwise one of the last true performance bargains out there.
As far as the roofline goes, concept cars don't always address the everyday realities of driving. Concept cars are designed to look really nice, but a low roofline, functionally speaking, is tough to work with as far as headroom, sight lines, interior packaging, etc.
