One thing I think might be cool for Q2 is to add masks to the textures that define the 'metalness' of a pixel.
So then you could change some parameters of your reflection model for some cheapish physical based rendering.
So no more diffuse reflection for the metals and you could use the existing color texture as the specular color -- well, I SUPPOSE
Non-metals just use the color of the light as specular color (though ideally you need to gamma correct or it'll look conveniently metallic anyway).
I noticed Quetoo doesn't actually do diffuse shading with it's normal maps (only specular) which I guess is why the metals look kind of nice.
The downside is that you can't do things like brick walls and such very well, but Q2 is mostly metal so it's a natural fit.
The radiosity normal maps are nice, do you get them out of a compiler or render them in engine somehow?
Also did you have phong specular on the surfaces before? I guess you can't do that with 'vanilla' RNM unless you make a deluxel variant.
But SSLR magic trickery is probably better
