It looks too uniform to really "read" correctly; you'd get a better look of age and grime if more of the weathering were settled into the recesses. A trick a former coworker taught me (that was used on the ships in the 2003 Battlestar Galactica) is to lay out all your UV maps, then bake out the ambient occlusion of a
clay render to a set of texture maps. You can swirl them around and break them up a bit in the image editor of your choice with bushes, smudge tool, etc, then bring them back into your CG software and use them as an alpha mask for your grunge shader, which will confine the dirt and grime to the cracks and crevices. You can also play around with the black and white levels to confine the mask more to the outer surfaces and edges and get some edge wear that way.
I also can't tell what material this ship is supposed to be. Is it blotchy plaint? Rust? You'll want to think about what material the ship is made of, if and how it was painted when it was new, and how that would have worn down/weathered over the years from radiation, dust, particles, etc. Did it get hit by meteors? Weapons fire? Give it a history and that can guide your texturing.
I think any surface or edge facing forward should be worn down to the base metal to account for space dust flying into it.
+1. The forward surfaces can be more worn/abraded, possibly with streaks running backwards over the surface to imply the damage was taken while flying forwards.
