Galaxy S5 does something similar with their interface when ringing and also during a call has a little hovering icon with the other party's image to let you easily jump back to the call details.

One thing I miss in Lollipop is that the battery usage screen seems to have removed the "time on battery" counter which is a bit annoying. This is on a Nexus 7 (2013) with the Lollipop (beta or preview or whatever it's called)