First - I'm glad you removed that terrible 3D ship.
It's obvious this is probably the best piece you've done so far. Although - nothing is perfect. I'll get back to it later, first - the highlights.
This piece has that beautiful classic SA feeling (except it's not hand made). At first glance I wouldn't even recognize all the other 3D aspects. Original sci-fi idea only supports this classical mood when all the Space Art artists were not influenced by science and their imagination had no boundaries.
Color mood is laso one of the highlights - no big contrast, but calm, soft colors that don't distract from details.
There are just 2 things that concern me a bit - the first one you already know - it's that composition - not really wrong, but a bit messed up. Too much objects together on small space. Space needs to breathe.. ..it's vast and silent - your is just.. ..crowded.
The other problem is with the overal "plastic" feel when I look a bit closer. Not a really big deal, but I must mention it. Probably caused by that 3D machinery.
Anyway - a good piece in right time. That's the way to go!