Larian Studios Forums Divinity - Original Sin Divinity - Original Sin - Enhanced Edition Keyboard & Mouse or Controller?

You can still switch to out of combat characters in the controller UI (left trigger).

KB/M allows you to change the party formations and has hide helmet options. Those options are not available in the controller UI, but you can set them in KB/M mode, save and then switch.

Inventory management is a little easier in the KB/M UI.
With KB/M you can hold Shift to queue commands to move or attack (ie to have a character follow a specific path), which can occasionally be useful. The controller UI makes it easy to target opponents, so you can not miss-click due to idle animations and move when you want to attack (which eliminates one of the uses for being able to queue attacks).