I think you're ignoring the fact that a product as familiar as the Google search page alters the search space you're trying to optimize. No matter how bad of an idea it was to add background images, the fuss that it caused was way out of proportion.

Any change that deviates too much from the current state of things has a huge amount of friction working against it. Whatever you think of the current design, I defy anyone to come up with a major overhaul that makes up for the loss of warm fuzzies the average user associates with the current home page.