Hmmm... seems like the opinions keep going back and forth. Maenas, I like that idea. Although maybe I'd do that on all of the dark blue sections just to keep it consistent. Right now I'm leaning towards that. I figure if the designs go radially outward (like you're suggesting), then they're working with the existing shield design (those alternating sections). If I did my original idea of something circular over top, that would be working against the existing design and make it look too busy.
Krule, so far I'd focused on the color transition for the horn. I still haven't done any highlighting in the dark section at the tip. The rope still needs more work, I plan to do more of a gradient going from the bottom to the top.
Darthmarsh, yeah, I've seen some nice work done with weathering over decals. I don't like relying on them for figures, but what others (especially among the vehicle modelers) are able to do is very impressive.