3D Touch Map Zooming
I put a quick example together that does this. If you have a 6s or 6s Plus, just press hard on the map to zoom in one level.
Also, this would be really cool if implemented in a vector tiles based map, like MapBox GL. Since there are no fixed "zoom levels" in a GL rendered map, you could tie the touch pressure and zoom more closely together. A light press zooming the map a very small amount, a hard press zooming farther, etc.