Yes, its mostly the buildings that need AImeshes. Any structures that would need to be used by the bots, like bridges that need the AImeshes created. The navmesh generator works around any objects using the colision mesh which can works fine for scenery type objects, like rocks. Once the Aimeshes are ready, then the navmeshes can be created for the maps. The navmesh generator was only optimized for small combat areas by DICE. Large combat areas need manual editing of the navmeshes, and I until AImeshes are available there isn't much more that can be done with the sp support for the existing maps.
Most of the capital ships need some recoding to allow bots to be able to use the weapons properly, which is why most of the space maps are not ready to be integrated with AI for the main mod.
So far, Yavin is the only full sized map that works well with bots.