It's done. They're sitting on it and won't say why. The way it's developed, the PC and Xbox versions are identical with the exception of the xbox using .ddx files and the PC using .dds files and the .nifs being slightly different. It's possible for us to convert .ddx to .dds but it takes forever. Bethesda obviously has the tools to convert in batches as they created the file format. You can already take the xbox DLC file and put it in your PC game, it'll just crash as soon as it has to access the content in those .ddx files.
It is possible it has massive game breaking bugs, even more so then on the 360 and that is why they have not released it? However I think they are just focusing on the 360 and trying to fix that, and they have handled it very badly. As if they had came out and said we need more time with it and to focus on the platform it is out for then things might not be so bad.
Yet they did not and the PC community are getting ignored.
I do not even want this DLC, I just want to be treated the same as a person who plays on the 360.