Removing the URL bar entirely is not possible now, since typing in URLs is still fairly common. De-emphasizing it (like I do in Browsr) is a step towards what you are talking about.
But why exactly are you doing that? I fail to see how a de-emphasizing of the url-bar helps. Especially from an UX-point of view.
I see only one advantage:
* less screenspace used
But some drawbacks:
* The primary way of navigation is not seeable on start of the thought to go somewhere else anymore (note: maybe not the most common way to go somewhere, given the bookmarks on the startpage and people using only google, but still the primary way when you want to go anywhere now and you understand urls)
* Relying on people understanding tabs
* Introduction of a hidden feature and usage of an already used interaction (double-click on tab)
It seems you want to enforce the opening of a tab when you go somewhere, especially since you have no dedicated and always seeable search-field. And your answer to the comment above implies you maybe want to think about a different navigation concept. Which all is fine in some part, opening tabs when going somewhere fits to my usage-pattern.
But i think that this development (as other browser-vendors try to hide the url too) is aimed at a specific class of users (google-only-users + bookmark-only-users + power-users reconfiguring their browser like they want), letting many other (e.g. all struggling users who just discovered the url) behind.
