Hey Francois, good to see you're still at it, this is in my opinion, one of your better pieces. You're not overreaching so much with this one. I'm not entirely convinced with some of the expressive ideas but there's a far more cohesive sense of whole here. Mjames rather bluntly points out one issue which is that some of the harmony isn't all that purposeful but to be honest there's far less excess in this piece than you usually do.
I would recommend that you don't lengthen this piece but rather write more works of about this length and complexity but in different styles and with different expressive goals. Perhaps a more cheerful piece next time? Just a thought. Anyway, good luck and keep it up.