It looks heavily corroded, which would make an interesting look. A few things to consider:
1. Weathering has to be consistent across an entire kit. That means all of your armor and your soft parts have to be equally degraded. If that's not the plan, I'd recommend some more sanding to smooth things out further. It's time consuming, but the final product will be worth it.
2. With that much pitting and flaking, some exposed metal, rust spots and blaster bolts will make the texture more believable as intentional. The usual process is to lay down primer, then a metallic coat of your choice, clear coat, mask off "damaged" areas, lay down another color, mask, layer, repeat as desired. Once you remove the masking, the helmet will look like it's been to hell and back and you can enhance the effect with washes and other effects.
3. I highly recommend cleaning up the corners and crannies so that the angles are sharper. You might have to make a sanding stick or use needle files like the ones available at Harbor Freight. Go slow so you don't take off too much material too fast.
All in all, it's a good foundation and I think you can elevate it.