I'm fairly well-persuaded that graphic design in concert promotion and flyers is at a bit of an ebb right now - or at least, the kind of poster designs you see miniaturized in ads in venues like local print editions of The Onion or in alternative weeklies tends toward the dull.
Often, it seems the images are sort of randomly chosen, sometimes with an arbitrary connection to the artist tossed in. A few months back, Iron & Wine came to town, and the poster image promoting the show was a creepy illustration of a barren tree whose branches had sprouted numerous iterations of Sam Beam's bearded face. Uh, okay - I can what that has to do with his music...
On the other hand, while being obscure can be annoying, frustrating, or an easy way out (i.e., can recycle image for other artists with no one the wiser), being literal is also a problem. Witness this image: The sound you just heard was the collapse of that image's designer's brain, sucked into the black hole-like gravitational vortex created by the image's mindbending obviousness. I mean, wow: I can imagine the thought process, the meetings, the endless e-mails that went back and forth until someone finally came up with this one: "Hey, the band's called 'The Walkmen' - let's use...a Walkman! And the opening act is called 'The White Rabbits' - how about...a clip-art rabbit image, and then we can just flip it horizontally so there's two white rabbits...geddit? Huh? Huh? Geddit?" SPLUSHHH! and they had to use a shovel to remove what was left of his brains from the office floor.
I'm only surprised the backdrop isn't a whitewashed denim texture - presumably, the band White Denim didn't have enough clout to get their name illustrated with such ox-stunning literality.
(PS: The Walkmen are still a great band.)