The shape is good and the detail is good. Could maybe use some more detail on the inside of the air intakes, vents or radiators or something. Could maybe use a door on the back and the rear engines look like they should have rail rotators. Systems are, as you noted, missing but I'm sure you can figure out the new system. I like the exterior lighting and your use of fractional blocks.
All around good shell, just needs a little finishing.
Also, Crimson Artist has a Sketchfab import guide buried in the forums somewhere, just search "Sketchfab". It should help you clean up the 3d model with transparency and such.
