Anyone who thinks album artwork isn't important is kidding themselves. In fact it's fundamental to the entire album "package". I'd go as far as saying it's even more important these days, as it's something of a lost art in the modern era of digital downloads.
It harks back to the 60's and the dawn of creative album covers as part of the entire experience of buying, exploring and enjoying an album. Imagine Revolver, Sgt. Pepper or Led Zeppelin III without their iconic artwork. They'd be different albums altogether. It's also probably the main reason I don't download albums and will buy CD's as long as I'm able too. Album artwork and creativity is still vital for the medium otherwise a fundamental part of music will die and people will just become lazy and stick out any old X-factor style garbage with just a photo of the artist on the cover.

Incidentally, I understand peoples reservation about the new album art. It's hardly the most exciting image in the world, and I don't think it does Noel any favours either as it seems to age him about 15 years. It's alright though. I remember being disappointed at Noel's last album cover, and the frustrating part of it was I felt that every one of the singles had far better artwork.