I disagree completely.
I don't particularly like iOS devices, and use an Android phone myself (Samsung SGH-T989), but I agree that it was in Apple's best interest to stop relying on a direct competitor for core functionality of their phones.
Apple is very much about marketing and branding. They want to be the hip, stylish, geek accessory that everyone wants to have. They want complete control over how their devices work, look and feel. This mandate has worked very well for them.
Google's requirement to increase their own branding in a pretty core function of the phone goes entirely against this philosophy. Suddenly Google is providing some cool features, and get's to advertise this fact to all of Apple's customers.
A mapping team wasn't just a good idea, it was an essential idea. The bad idea was releasing it before it was ready.
Apple should have either (a) bit the bullet and delayed the newest iOS launch, (b) used Google for one last version, then kicked them out in the next version, or best yet (c) written their own mapping software a long time ago.