I like it, simplistic in it's nature and tell's you how the music is gonna sound. Stripped back to just those four guys and that's it.
Also, isn't The Joshua Tree front cover effectively a band front cover and a lot of people regard that a classic. The front cover of this might be a little nod to that record, if you believe reports from Q stating that HTDMAAB is as big in theme's and tones as TJT.
I think they've went out of their way to lose the irony of the 90's front covers and the over load design style of them (which I really liked). It's a love it or hate it front cover, but it looks like it's here to stay.