The ostinato became less and less functional in the chordal and textural structure as it went on. This is my main issue, I guess. I would probably change it up a little bit in that beginning section occasionally, since it begins to clash with the rest of the ensemble.
Obviously this genre is not inherently classical, but the middle section has a lot of pauses that take away from the energy/relaxation, at least for me. It made everything feel strophic and repetitive even though I objectively know that it's not.
Overall, though, it was nice to listen to.