Very nice!
Loved the pizzicato strings with the woodwinds. The glockenspiel is one of my favorite instruments for carrying that "magical" sound.
Concerning your tutti, it does have a slightly hollow sound. In listening closely, it does sound as though you have most registers filled. I would check to make your your cellos and basses are an octave apart and not in unison. I can hear your trombone triads, but their volume is very low. Throughout most of the tuttis, you have many instruments playing octave melody, which is pulling away from the harmony a bit. Believe me when I say that this sort of thing is what I find frustrating in orchestration myself. You want a melody that sounds strong with many the instruments playing it, but you need some nice strong harmonic triads to bring out the harmony more.
I would probably not have the tubas and upper trombones playing the melody too; I would keep them strictly in harmony so you buy back some of that support power in the bass. Really all you need for the melody are the violins, flutes, and probably some forte horns.
That's just my opinion, anyway, based on my style of composing. What you have here sounds great!