When i first started this game i was thinking, same with other people that instead of just Tamriel we should get some other areas of Nirn and also more daedric realms but then after a few days of playing i saw that we visit almost all of the daedric realms already and also many of the areas outside of Tamriel through portals in quests so there really isnt any point in adding them as more areas it would be a waste of memory, we should just get the Tamriel completed and continue visiting the other remaining Nirn areas this way through quests in Tamriel. The reason that Coldharbour is an acctual questing area is because Molag Baal is the main antagonist of the game so its normal to have his realm as an extra area outside of Tamriel but otherwise for the rest its good as it is to visit them through questing.
Old TESO Player