That address field feature is a cool idea. I'd expect other browsers "copying" it soon, which would make it another item on a list entitled "Invented by Opera, popularized by others".
> Parameters at the end of web addresses are visually hidden when the address field is not focused
I think those are terrible, terrible ideas; to the best of my knowledge this behavior was pioneered by Chrome and is now growing like a cancer, under the false premise that "non-technical users don't understand urls".
How are they going to ever understand them if browsers don't show it to them??!? Hiding query parameters breaks the relation between a url and its content; now all of Google is under the same "www.google.com" url: how is that "better"?
By the same principle that "young people don't understand words" let's remove all printed words and simply print books with the same cover and the same title -- they're all "books" anyway.