FC said the booster pack includes land control and improved graphics/sound.
This does not mean that it will only include these.
Anyone reading the forums will know that FC don't like to give info away for free. I am guessing there will be other things in the pack.
The pack is going to have to be large (they say the reason for a CD rather than a patch) so not only new meshes/textures. I am expecting a few more things that take up space (ie a few more static dungeons and maybe 1 or 2 more areas.
Knowing FC, they don't know exactly what they will be able to it in the pack, so they are keeping quiet. Lets hope that there is a load of other cool stuff in it.