I actually like the ABB cover a lot, because it has a kind of old fashoined feel to it. Looks like a cover from the sixties or early seventies.
If they wanted a cover that catches your eye in the shops, a lighter, simpler cover would have done the trick. The best (relatively recent) cover in that respect is the one of Voodoo Lounge. Forty Licks also was a decent one (light one with the trade mark logo).
compare:
Also I would use the tongue/lip design more often in marketing campagnes. It's one of the best known logo's in the (music) world. The new "melting tongue" looks pretty cool to me, but has lost the significance the original has. The Forty Licks version was better.
I don't know wether it has any influences on sales, but I personly would have selected another cover (and tongue/lip design) for A Bigger Bang. It works for me, as a fan, but does it attract enough attention?
regards, E.