(suggestion) Option to right-click a navigation history item Rated 5 out of 5 stars
The right-click can be used to open an item in a background new tab or even open a small context-menu with different options to open the item.(same tab,new focus tab or background new tab)
Right-click is much easier than middle-click in many mice.
like Xyzzy said - give an option to display the history item when hovering OTHER tabs (for those who don't use Tab Scope addon)