Menubar, bookmark bar and even tab bar don't always serve a purpose. A more modern feeling way of browsing could be giving websites more space and making controls pop up either when moving mouse up as currently, or on a mouse button press maybe even in the form of overlay type buttons and searchbar in the middle. Some indicator for tabs probably need to be constantly present for a lot of users though, so consideration has to be put into this. Also addons that function as notifications would need popup animations.
Basically a design approach that touch screen apps already get should be avaliable to desktop usage too, just for the screen space and modern controls IMO, as an option.
Also let me visualize and access bookmarks in useful modern ways too.