I took your advice, and made a more realistic rendition. Think the dynamics are working better now?
I used higher quality sample libraries, and made slight tweaks to the score. (This is a performance score, hence the strange note lengths and dynamic extremes.)
Have to think of a second subject now, to extend the piece. Think I may go with an atmospheric vibraphone and glockenspiel duet, with some tomtoms using feathered beaming.