User blog comment:Saratje/PC release date explained - Skyrim: Dragonborn DLC/@comment-4269579-20121230031418

I understand what you're saying that Bethesda doesn't see Hearthfire as DLC as required by whatever deal Bethesda had/has with Microsoft. But the issue most people are going to find with that idea is that DLC means Downloadable Content not expansion. As stated in the original post Hearthfire would be considered a content pack which is still Downloadable Content regardless of how Bethesda views it.