Thierry,
I've listened to this quickly, and offer the following,
firstly, good structure.
You have the lead violin pretty well on the melody for almost the entire part, or at least the same pitch envelope, be it first or second Vl. I would have liked to have heard the tenor instrument (viola?) get just a little more work, and even take the melody in sixths with the cello (for example) freeing up the 1st violin for a counter variation, with the second VL providing a wisp of rhythm with soft offbeats, an effective tool when writing melody in the bass, and giving a sense of motion.
And that tenor line is rather quiet in places, leaving the harmony a little hollow. Nothing wrong with that of course, many people tend to over orchestrate, so you're ok there, but when the 1st and 2 vls play in harmony, the Viola could do with just a little more.
Some variation in tempo could be good too, at the end of notable phrases. For example, early in the piece you have a silent pause. The short phrase, say 1 or 2 bars before could ritard. Then the resumption of tempo after the pause has a little more impact. In about the middle (and i apologise for not timing this as i listened) there's a lovely cello line followed by some wistful harmony as the lead line resumes. Perhaps a slightly reduced tempo and dynamic could heighten the 'wistfulness', and again, when you return to tempo, and brighter dynamic, the variation has a little more emphasis.
Finally, i wonder, more to myself, if the answering rhythm parts, mainly the two inner voices could do with a little more variation. If you've ever played the Merchant of Venice in a theatre setting, you'll understand that page after page of offbeats can be tiresome, not only for the player, but the listener too.
You've written lovely counters in the cello, and apportioning a couple of those phrases to the viola or second violin could make a difference tonally, and lift this even further.
I enjoyed this, and would like to hear it again. I will say my comments are only suggestions, and not a criticism of your work. It's a delightful melody, and that's something missing from so much music today.
A good melody.
Regards,
Alex.