A new generation of users are coming online whose experience is predominately a mobile one, and on touch, sparse, touchable, explorable interfaces are the norm. If Google simply kept maps the way it has been for a decade, sooner or later, they'd find themselves criticized because it doesn't work like "Apple Maps".
In fact, people seem more willing to adopt radical new user paradigms if the form factor changes. If I change your desktop email, you'll get annoyed, but if I create a radically new out of the box mobile email experience, you'll be more amenable to learn it.
Or, you know, they could have changed them into something better, either incrementally or in one step, instead of the new broken design.