Exactly. This wasn't intended to be negative, and I have no problem with 5 or 6 types of dungeons, because everything inside should be customized.
Well, the way it was explained to me is how Morrowind had Cave, Mine, Dwemer Ruin, Dunmer Ancestral Tomb, Dunmer Stronghold, Velothi Tower, and occasional combinations thereof. Oblivion had Cave, Ayleid Ruin, Ruined Fort, Oblivion Gate exterior, Oblivion Gate interior, Sewer and combinations. Skyrim will have Cave, Dwemer Ruin, ?, ?, ? and ?. Within each of these types in all the games were several unique things, so that the caves in the Bitter Coast were not the same as the caves in Sheogorad, or the Nibenese caves were not quite the same as the ones in the Valus mountains. Skyrim will likely be doing exactly the same thing.