So I just did a daily quest in Northrend for the Sunreavers (Silver Covenant). The quest involves you getting some flowers for a lonely maiden in the Drak'mar lake. Quest
So you get her the flowers and she says the following words: It's been so long since a traveler has come here bearing flowers. The lake has been too lonely these past years. The travelers stopped coming and evil came to these waters.
So from these words I can only assume that Northrend was not always the scourge infested land it is today. What was it like before the scourge and before the Lich King?