This is a great thread.
I also consider the melodica to be an expressive instrument. I come from a piano background, classically trained, but ended up working as a composer. The piano is a great instrument, but the state of most pianos in venues and studios leave a lot to be desired. So you end up playing digital pianos most of the time.
Having a small instrument I can take with me is what I’ve always wanted. Add to that the benefits of breath control, and the melodica opens up a lot more expressive capability. So compared to the piano, its a highly expressive instrument!
I completely agree with you Lowboy, that the harmonica has some fantastic expressive capabilities. I’m a great fan of the instrument. But it’s so closely related to the melodica that its tempting to compare, and see the melodica as the more limited sibling. But remember it is a different instrument, and it has strengths as well – you can play a whole range of chords and intervals. And the sound projects much more without amplification, making it a real contender for acoustic music.
It just looks a bit funny 🙂
I constantly work on technique, and am always attempting to make my experience of playing easier, more fun, more throw away. I find that this brings about a natural expression in itself