-The app always loads with an "Explore {your_location}" card that takes half the screen. I am usually at my suburban house, near which there is nothing worth exploring. Even when I'm somewhere else, my primary use of the app is to get directions to an _already determined_ destination. The card is useless 95% of the time, but obscures half of the map, which is what I want to see and is so important as to be the name of the application.
-If I so much as brush the screen with more than one finger, it enters its 3D map mode. Like the "Explore" card, this seems to be screaming "look what we can do!", but it ignores what I want to do, which is navigate using the bird's-eye paradigm that has been used by every other map since the dawn of cartography.
-If I search for a place and tap a result, I get a full-screen card with information about that place, but no map. I just searched for "pizza" and tapped the first result and got a large picture of a pizza. I already knew what a pizza looks like, but I still don't know where the restaurant is. If I swipe the card down and then tap the map to try to get a better view of the restaurant's location, I lose the location indicator on the restaurant and the map re-centers on my current location.
I could go on, but I feel like an old man shouting into the void.
I do not have "Start AR" at the moment so I cannot test that.
I agree on annoyance with "design changes" sometimes. Last weekend having the map always oriented to the North was driving me nut. They used to have a compass with a N to toggle it. While I was driving it took me 15 minutes to find the option under all the advanced options.
But that said I think Google is in general pretty good in trying to reduce the "featurite" in the app and simplify the UI.