When you use "Open URL / Open URL with selection", If the given URL is already opened in the browser, it would be awesome if BTT could switch us to the given tab instead of systematically creating a new tab.
This would open a new range of possibilities by allowing us to associate shortcuts with specific websites. For instance, I would love to be able to set a shortcut to access my "open.spotify.com" tab in one shortcut, but I don't want to end up with 50 Spotify tabs at the end of the day.
For inspiration, Slapdash manage to offer such functionality thanks to their chrome extension. (If the page you want to open is already opened in the browser, it will bring it to the front instead of opening the page in a new tab)