Possibility to access menu-bar items on the right side (like WLAN or BTT menu-bar icon)

It would be nice to be able to access the menu-bar icons on the right side of the bar as well to access little helper programs that have no keyboard shortcuts for their actions.

For example to change WLAN Networks really easy without using applescripts or to access apps like EasyRes to change the Display Resolution or smcFanControl to change the fan speed.

This is not possible in a generic way as there is no standard to how the menus are built.
You could use automator to record a workflow and then trigger that workflow using BTT. This will work for most items.