Street view is there in Maps on iOS. There is an icon that looks like a person on the details of any push pin or the current location pointer. Touch it, and you zoom into street view.
See my other comment - street view doesn't exist in directions on iPhone. The Android term for it is 'Navigation' but it amounts to seeing the view you'd see with your eyes, with a fat arrow pointing you where you need to go.
It's really useful, especially as I've only lived in London for two years.
