Well, I can tell you how I did on mine. First, I coloured the selected (yes, I do select areas when texturing) black, then used a red brush with 35% opacity to make cracks, then went with the same brush over it again, and finally used a bit of orange for certain areas. The stones I simply coloured with 25% opacity and dark grey. After all that, a hefty Sharpen Edges filter.
EDIT: Oh, and about the armour being bland and stuff, remember, Wc3 tends to make detailed textures a horrible blur. The amount of detail is at the perfect level right now.