The agency I work for has been tasked by lots of clients to enhance their brand, and we, as designers, have been mainly concerned with how things look. These same clients will have depended solely on us to manage their branding so it has been up to us to educate clients about how else their brand can be improved (apart from using visuals).
The opportunities can be uncovered quite easily – you just have to ask the following: how should the brand look; how should it smell; how should it taste; how should it sound and how should it feel?
After all, admit it, you've smelled every book you've ever bought, right? . . . right?
Mood Media and Air Aroma are two starting points if you're interested in learning more about developing the customer experience sans graphic design.