I think the phone looks great. The design is still Lumia in spirit. But the big difference here is this time, the phone is designed for a different OS. Back then during the 920, 800 or even the N9, it looked beautiful because the OS were beautiful likewise. The tiles and icons over the super black screen made the bezels irrelevant. The yellow tiles would compliment the yellow phone. the curved glass complimented the way the OS worked. Windows Phone 8 was left and right swipe heavy, thus, the curved glass. Nokia designed phones with the OS it was putting it in mind. They even put great effort and created and designed wallpapers even ringtones that worked well with the design of the phone. everything looked and felt cohesive.
I have to admit that Windows 10 mobile would look a little off if put in past lumia phones.
This time, Windows 10 mobile went into a radical redesign leaving behind the minimalist look. Gone are the floating live tiles, the bezels are more noticeable with the addition of wallpapers. Even functions of the OS made radical changes. Former Nokia designers are challenged to work around this and made design decisions with windows 10 in mind. I believe this is still work in progress, Microsoft mobile has yet to develop a hero screen that works well with that design because the OS it's gonna run in is also a work in progress. This is just a preview.