Very nice use of orchestration- a great blend of instruments and timbres which does not grow tiring at any point.
My main advice would be to seek opportunities to record more of these parts live. A lot of what is lost by virtual instrument performance is the detailed phrasing that is simple in real life, but extremely difficult to replicate with samples even with great experience. Your musical style, centered around a few exposed solo voices, lends itself to being recorded very well and I think that's probably the best first step forwards.
Second to that, consider exploring more deeply how to phrase each line. Players don't just slur every note together or play everything constantly the same length or dynamic of staccato (well, if they are given the choice). The shape of each line also can be expressed much more, both in dynamics and expressive qualities like vibrato and where slurs are made. If you aren't sure what I mean by all of this, go listen to some live players, regardless of genre/style and imagine what they are playing is something on a piano roll. Consider which notes they make shorter and which they slur together. Consider that a phrase is always 'going' somewhere- and should (almost) never just be standing still. How is this achieved in reality? How can you achieve this in virtual writing? It doesn't matter if you're writing like a 90's video game composer or a modern orchestral mockup artist, phrasing is one of the most important differences between a good track and a fantastic one.
Edit: here's a very simple example of a four-note ostinato being phrased several different ways I put together a bit ago for someone else. Notice how each method gives a different sound to the ostinato, yet with only the same notes, just playing with where the slurs are and the dynamic shape-
https://instaud.io/2TY8
My main advice would be to seek opportunities to record more of these parts live. A lot of what is lost by virtual instrument performance is the detailed phrasing that is simple in real life, but extremely difficult to replicate with samples even with great experience. Your musical style, centered around a few exposed solo voices, lends itself to being recorded very well and I think that's probably the best first step forwards.
Second to that, consider exploring more deeply how to phrase each line. Players don't just slur every note together or play everything constantly the same length or dynamic of staccato (well, if they are given the choice). The shape of each line also can be expressed much more, both in dynamics and expressive qualities like vibrato and where slurs are made. If you aren't sure what I mean by all of this, go listen to some live players, regardless of genre/style and imagine what they are playing is something on a piano roll. Consider which notes they make shorter and which they slur together. Consider that a phrase is always 'going' somewhere- and should (almost) never just be standing still. How is this achieved in reality? How can you achieve this in virtual writing? It doesn't matter if you're writing like a 90's video game composer or a modern orchestral mockup artist, phrasing is one of the most important differences between a good track and a fantastic one.
Edit: here's a very simple example of a four-note ostinato being phrased several different ways I put together a bit ago for someone else. Notice how each method gives a different sound to the ostinato, yet with only the same notes, just playing with where the slurs are and the dynamic shape-
https://instaud.io/2TY8
Sample library developer, composer, and amateur organologist at Versilian Studios.