You can install our site as a web app on your iOS device by utilizing the Add to Home Screen feature in Safari. Please see this thread for more details on this.
Note: This feature may not be available in some browsers.
I know from using my iPhone as I'm sure some of you are too that Google (atleast for iphone) isn't the best navigation app out there. It won't give turn by turn or recalculate your route. The only thing I like about it is you can overlay satellite picture and map views.
On the UI I also hope they will make a layout that makes certain more often used buttons more distinct or like TEG said make it user adjustable would be even better.
I am not sure OLED is the answer. I have an HD-DVR and an MP3 player both with OLED, and they both wash out when hit by direct sunlight. A really high quality LCD might do better from what I have seen.