Bingo Matt! iOS has needed a default app API forever. Microsoft was mandated by governments to make this painless in Windows. IMO, iOS is getting to the point where to a developer, it's practically a monopoly. You can possibly make a living doing mobile apps for some other platform exclusively, but striking out iOS is a huge (potential) loss to the bottom line.

That said, I'm not sure the default app thing will have as much of an appreciable impact for maps. I can't even think of a single time I've ever been directed to the maps app via another app, unlike with mail, safari, photos/camera roll, phone, messages, etc.