Thing is, sometimes the stuff that comes "too easy" ends up being your best work. Much like the writer who does his/her best work at the very last minute. You can't force something just because you feel you should take more time/start earlier like everyone else. Some creative types are like that. I suspect U2 are the type of band that does their best work on the first or second try. Where they've run into trouble over the last few records is they've lost their confidence with that first or second take. The result is needless revisions and productions that ultimately dilutes the final product.
I think Danger Mouse is the type of producer that really brings the best, most creative sound out of the artists he works with. U2 needs to do less questioning and more trusting.