I agree that the UX of Google Maps isn't great, but one thing that might not be quite fair in the critique is the point about having to enter the origin destination. On mobile, I'd venture to guess that most of the time you simply want to get somewhere from where you are right now. So I personally don't see the origin destination as something that I need quickly accessible. I enter address, click when it auto-populates, and click to navigate. It's usually 2-3 steps for me on Android and I'm ready to go in 5 or so seconds.