The DLC contains more than just the dwarf bar.
There's the tables and bar, along with decorative spilt beer. There's rail tracks, ore carts, and miners, along with a selection of different coloured mine walls. The pit traps consist of open water, stalagmites, and ore crushers. There's also ice walls (one which contains frozen trolls

) and ice floors & patches. We also have stalagmites and stalactites as decroative features.
That's all I can remember, but I don't think there's much more. It all looks as pretty as ever though

Edit: and there's the dwarf arches too, along with strip lighting (ceiling & floor).