I would just eliminate the URL bar and the back button entirely. These concepts are relics from the Internet 1.0 age and no longer have the correct meaning. Some sort of bookmark/search/wiki replacement navigation system needs to be developed.
There are a lot of non tech savvy people out there who are so afraid of breaking things that they won't even open context menus in Word without saving their document first. All of those use facebook and the web like champs because they can never totally screw up because the back button takes them to safety. Don't forget, many grew up during times when using technology wrong meant that you would loose an arm. Back button fixes that anxiety.
You simply can't rip out a UI convention like that. Think about how many browsers there are. Virtually all of them use the back button and an URL bar. Say you made a browser without those, with an innovative new navigation system. Think it'll catch on? Extremely unlikely.
When you take out one of the oldest conventions in the book, people are going to use it for five seconds, 95% of them will decide they hate it, and will simply use what they're used to.
Consider iTunes 10. iTunes 10, released only a week or so ago, changed the UI in a minor way. Somewhat minor, anyway. Here's a screenshot: http://cl.ly/2OWb
Now, this looks a little different to your average Mac OS X app. Judging by my twitter feed, about 80% of my followers changed the window controls back to the old style (http://cl.ly/2ODf) as soon as the option became available.
They did this despite the fact that it makes sense. Having the controls vertically saves space and provides an extra thirty pixels (or so) to view their music.
Making sense doesn't matter in even rather minor UI changes like that. Like the old adage, a frog put in boiling water will jump straight out, but a frog being boiled will never notice.
Consistency is key when it comes to UI conventions, and it's _extremely_ hard to change the tide. The only way to do it is if other leading people do it also.
For example, Opera started using tabs on top at about the same time as Chrome did (don't quote me on that, I'm trying to make a point). Then Safari tried it, and now Firefox 4 has tabs on top as well. The only way to facilitate change is to not be alone in making it.
Furthermore! "Some sort of bookmark/search/wiki replacement navigation system needs to be developed." Do you have any ideas as to how to implement that? (I'd honestly love to hear them, I'm not trying to bee too much of a sanctimonious dick. ;))
It really needs to be split into 2 buttons: "Back" and "Parent" (or "Up"). People use the back button for both purposes. And when you involve Iframes and Ajax-heavy web applications, the context of "back" gets entirely lost and broken.
It's a big problem. There is an HTML5 api to give some level of control over the back button, and this may help to a certain degree. But I really believe it would be preferable to just move these concepts (navigate back and up) right into the web page, or the web application.
There is absolutely nothing preventing web applications from giving a superior navigation experience than a one-size-fits-all web browser buttons.
By web application, I presume you mean for example google docs, rather than a browser.
This would make it even less consistent, wouldn't it? Some pages/apps wouldn't have these controls, or they would look different or be in different locations across different pages/apps.
"Back" and "Up" are virtually indistinguishable for an average user. Hell, I'd be surprised if I could give a good description about the difference, and I know computers inside-out.
> There is absolutely nothing preventing web applications from giving a superior navigation experience than a one-size-fits-all web browser buttons.
Except for the users...
Microsoft Word does not have a back button. What operation should a back button perform in Google Docs?
>"Back" and "Up" are virtually indistinguishable for an average user.
Sometimes you want to go "back" to the main page of a domain. Other times you just want go to the previous page. Other times you want to leave the website entirely. Other times you want to "undo". It simply makes no sense for a web browser to try to support all these features based on a simplistic web browser history based on URLs. It's an ancient way of thinking about the web.