Hi! love this new concept, this can really turn out awesome :3 now for my crit-op xD
I really like how values look on one of those first (orange) process images you posted, so I reduced the contrast and made everything to be very midtone-ish and build it up from there.
• Other then actual values, what can help you separate elements is also line width and the value and sharpness of the line itself. That's what will make your details clearer: For focal part of the image you can use thicker and/or sharper lines, and things that are not as important can be less tight. When setting up main values of the image you only need, like 2 or 3 main shades (like with color design), none of them need to be pure black or white — those are for final touches mostly.
I don't know what kind of atmosphere you had in mind, my OP ended up way lighter ^^; but even darker version like yours could work if you keep these things about lines and contrast in mind. Most of the super detailed and contrasting stuff is where our focus is (or where the main light source around his head is) the rest can be looser...
Here's list main points I changed so you don't waste your time trying to find the differences xD
• Reduced contrast overall in whole image, added darker values and strongest highlights in head/shoulder area as that is the main focal point
• Made lineart thicker (and darker) in some places so it has stronger hold of the details. Your lines are way too light ( you could say "shy" xD) to hold the form and details of hard surface creature like this, so that's why they are "spilling out"and getting lost in grayness.
•I curved the tail-pipe things above him to match the ones in the orange image because I feel composition-vise it flows much better (and also, like @tck I moved it more to the center)
•Added bit more highlights on the arm holding the staff (and removed hglight from the staff itself, I don't think it needs it as much) to emphasize that light source.
I hope this isn't info overload and it actually helps you xD Good luck! 
