Peter Pachal for Mashable:
Sagi Haviv, who designed logos for the Library of Congress and Armani Exchange, thinks the logo simply isn’t distinctive enough. By opting for a simple array of four colored squares, Haviv says Microsoft missed a big opportunity…
…As Haviv explains, logo designers constantly struggle to create imagery that’s both simple and distinctive. Too much of one often means not enough of the other. In Microsoft’s case, he says it veers that while the new logo is definitely simple, it fails the distinctiveness test.
I agree. Microsoft had the opportunity to really try something bold here but instead they went the ultra conservative route. You can see a similar designer debate over at this Dribbble discussion.