A problematic functional design issue in XenForo is the abundant use of tabs, which are hidden on small screens. 70% of our users are on mobile these days so this poses a challenge. The current way of handling tabs hides most of the content available to the majority of our users.
If a site has multiple addons then /find-new/ and profile look like a wall of bricks:
This is not intuitive nor good UXD.
A method that this issue is handled in successful apps is the use of horizontally rotating tabs. You can see it in action in many apps, like the BBC News App for example.
This method allows the mobile users to swipe and rotate tabs in an intuitive way. This could be implemented for small screens only or enable mouse scrolling to rotate.
Here are some examples: