What I think needs improved or rather, scaled down are the node icons they're far to large imo. The icons that reside to the right (thread/post and subforum icons) could do with undergoing a re-design. For me they look a little low quality compared to the rest of the theme so I think re-visiting them perhaps not introducing a gradient on them will give them a crispier/sharper look.
I'd also remove the grid like gradient in the background, I think a one colour non pattern effect is the way to go with this.
Overall though, shaping up very nicely.