Looks almost like you're using it as a wash. I don't think it's overdone, per se… I liked in the YouTube vids GW put out, how they used it to build up in the cracks only and then some streaks. I actually think what you've got going there is a nice start, but I want to see more, believe it or not. How are you applying it? Straight from the pot or cutting it with some kind of thinner/water? I think some of it looks great, like on the Martyr's right hip ball joint where it came out really gritty and grainy. Other spots, less likeage, like the rear piston of the same leg where it looks a bit too washy. I think in general though it's good. Adds a nice 'lived in' layer of grime but not over the top yet. I want to see it GO over the top, personally, but that's just me.
Doing the super zoom-in (hey, I won't judge) it looks pretty solid in some spots around the rivets. Especially around his left hip. I guess maybe there should be a concern about the inconsistency? I mean, grime and weathering won't be uniform, but in terms of application any idea why the results seem to vary?
I think from here, if you were to add some scratches with a brighter metal color to show more recent nicks, it would look really cool. Much, MUCH better than the typical "Boltgun Metal, nuln oil, dry brush Necron Compound" that almost all of them seem to be. Don't be shy, man. Let your dirty side shine, er… NOT shine. Or something.