The new Forum theme is definitely a step in the right direction
Here's some specific feedback:
In the above image,
A - this margin is now far too bright (i.e the bit between the dirt backdrop and the dark green colours of the posts), I'd suggest darkening this to a shade just a little bit above the backdrop.
B - the orange for names doesn't seem to go with this theme any more, I would suggest either navy blue or a very dark crimson/burgundy, to compliment the brown backdrop.
C - I'd also suggest a darker shade of blue than this for titles, links, etc. Maybe just a few shades lighter than navy.
D - backgrounds for quotes now need to be a much darker grey; it looks too "highlighted" within the post.
And, in this image, the green in the background (behind the logo) is way too light compared to the now much darker dirt backgrop. If the two were more closely matched, it would definitely be an improvement:
Pretty much everything else looks just grand for now. I'm sure other things will come up as I browse the Forum over the next few days, but my initial impressions are generally positive. Nice work!
EDIT: Another quick thought - maybe try switching so that the post backgrounds are shades of blue/slate grey and the link/topic text is dark green.