We now have switching information communicated from the game to Wwise for three different aspects of character sound:
The combination of these switches when the Footstep event is triggered by the game will cause a sound from the correct character, step and surface type sound object to be played. Now instead of having multiple events to keep track of, we can simply pass a single event for a 'footstep' from the game and let switches handle the correct playback of sound as defined by the game.
Another technique used sometimes at the content level is the separation of heel and toe variations. This adds further diversity through randomized combination and, if the content is designed appropriately, can exponentially increase the variations and further reduce the chance for repetition. By setting up a sequence container with a randomized Heel container (1) followed by a randomized Toe container (2), each step can be composed on-the-fly when a footstep is requested. Further memory savings may be possible if you're able to share heel or toe components between different surfaces. By working elementally with the techniques available within the Wwise authoring application, you can increase variation and reduce your memory footprint, which is a winning prospect for any development.
Regardless of the level of detail your game and implementation requires, Switches provide an efficient way to deal with groups of content whose playback is dependent on information from the game engine.