I don't understand this obsession with complaining about copying or imitating in design. As long as good things are taken and worse things are left behind, the consumers benefit. It's like being upset that the 2014 cars have the same steering wheel and pedal layout, or that a manufacturer "stole" the idea of using a USB port in a car.
The "Can't quite put my finger on it..." piece is in reference to a common catch-phrase for bloggers who have mocked Android, Samsung, and Microsoft for "copying" elements from iOS. I agree the whole back and forth is a bit silly from both parties. Edit: missed a word
Only this is not a copy. It's just a different flat design, just as Windows also uses a flat design.
It doesn't copy the look of Windows Phone -- it just uses a similar flat visual language.
We cannot say the same for, e.g., MBA look-alikes that you cannot tell apart from 5 feet away.
It's like the difference between two manga comics by different artists (of course there are similarities: they used the same visual language) and a cheap rip-off of an animated series (e.g Power Rangers vs Powerful Rangers).