I've posted about this topic before, but a book I'm reading, Healing with Form, Energy, and Light by Tenzin Wangyal Rinpoche, prompted some further thoughts on this subject. In the book he explains that while five elements may seem too few to account for the diversity, he feels that the five elements can be continually developed into more subtle divisions. And it's a good point he makes. I think if you examine any model of elemental magic, you'll find a similar rationale. But I disagree with it, and while I respect that such a model does work for many people and is traditional foundation for elemental magic I think that why I disagree with it boils down to a sense that while you can associate a variety of attributes to a given element, it doesn't accurately portray those attributes. What it does do is provide a way to categorize behaviors, activities, etc into a particular element so that you can in turn say "X activity, behavior, etc., is like fire." This categorization gives people a way to conceptually understand something, but it also limits that understanding to the context of the association, and this limitation applies both to the element and what's associated with the element. In other words, if I associate certain attributes with fire, I limit my understanding of fire to those attributes.
In my own work with elemental magic, I've decided to treat whatever I'm working with as its own element. For example, instead of associating movement with a classic element, I've made it into its own element. By doing so, I feel that I can interact with and understand movement in a way that wouldn't be possible if I lumped it into another element. In my own approach to elemental magic, I've discovered that working with a given concept as an element in its own right has been more useful because its helped me really engage and understand how that element shows up in my life. This has allowed me to apply that concept more meaningfully to my life and practice because I'm exploring it as it is instead of trying to categorize it.
A traditional model to elemental magic focuses on categorization because its an easy way to understand an experience that's happened. But are you really engaging an experience when you can just categorize file it away? I'd argue that you really can't engage an experience unless you are willing to directly take part in it, which means shedding any categorizations you have and just allowing yourself to have the experience. In working with movement, as I recently shared, I discovered and am continuing to discover a lot I didn't really know about movement and wouldn't have thought of, if I hadn't been willing to treat movement as an elemental force. Now, you might argue that by treating movement as an elemental force, I'm still categorizing it, and you'd be right, by I'm not associating it with other elements, but instead treating it as an elemental force in its own right. And it may be that I am limiting my experience in that way, but I've also found that I'm still experiencing more of movement than I'd ever experienced before.
The same has been true of my work other elements, including the classic elements. When I worked with the element of fire, I had a hard time initially weening myself from the associations I had with it, but I found that as I stripped those associations away, I ended up having a different appreciation of fire as an element. It was much more primal than how I'd thought of it. I'd challenge you to consider taking a different approach to your own elemental work. Instead of sticking with the classic associations, try to just experience the element as it is. It may gave you a different insight and relationship than you'd previously had.