Let me state up front here, that I’m a fan of complexity in music.
I like things to be tricky, obfuscatedly opaque, not clear, and at times downright confusing. Isn’t the reward greater when you have to work to understand or get to grips with things?
Having said that, when writing you will rarely go wrong with simplifying. Even if you strip everything back only to build over it again. Perversely, simplicity does not mean your music has to be simple.
If you can get to the root of your ideas, and know them in their simplest form, then you have more concrete options going forward and you’ll probably feel that you “know” the idea more intimately. It’s easy to use ideas flippantly but if you spend some time figuring out what you have created, in it’s purest essence, you should have a deeper understanding of your own artistic process!
Simplicity not only means creating something in a clear, straightforward way, but also creating something that is straightforward to experience for the listener. That’s not to say it cannot have depth, complexity, or more than one meaning, but that the information is presented in an exceptionally clear way.
Once again, this is where genius resides. Think about some of the greatest pieces of music you know of, the ones you admire the most. Do they not communicate directly to you, even if you don’t know what the message actually is?
Often the music will be simple, but communicate something “ethereal”, something you cannot quite pin down, but which has meaning to you. This is the result of handling complexity with a light touch and making the result a simple, yet rich and complex experience.