Thanks for the suggestions everyone. Been very helpful. Took me a while to respond because I came down with a sinus infection over the weekend. Kinda deterred my progress. Anways, here's where I'm at with shading so far:

I made some tweaks to the geometry. While I did follow the reference image, some of its flaws really started coming out when shaded. I removed the top piece and made a small spike that is part of the head. I also lowered the handle and made the shaft bigger in turn. I also gave the handle some curvature for ergonomics.

Now that the mace is shaded, I think part of the reason it still looks very fake is because there is no detail. I'd like to add inscriptions, pattern designs, etc on the bronze areas but I'm having a really hard time making it work. I did some swirls in illustrator to use as a displacement map but the displacement effect looks really really bad on precise shapes. Works well for noise though. I also took the Carrara manual's recommendation of adding a subtle noise to base colors in order to remove the overly-clean look of flat colors.

Recommendations will be appreciated.