I tried adding q3map_lightmapFilterRadius to the shadow receiving surface (all the non-light emitting textures) and it seems to work, but this isn't a good idea since it means that basically all surfaces in the map will have filtered lightmap shadows, whereas adding it to the surfacelight shaders will mean that only surfaces within range of the surfacelight will be filtered.
Currently, I don't get any filtering at all, it's as if I didn't have lightmapFilterRadius at all. IIRC, it does work on surfacelights as well as sun/sky lights.
On the other forum, Fracman is getting similar results, no lightmap filtering with surfacelights - so at least it's not just me doing something silly.
Here's a screenshot using the shader above with r_lightmap 1:
... and the way it should look like with lightmapFilterRadius 8 0 on the non-light-emitting (wall) shaders, forcing lightmap filtering on all lightmaps.
The other issue that I'm dealing with has to do with ambient occlusion. It creates some odd results along the edges where surfacelights meet the other surfaces. I was wondering if there's any clever workaround.