Wrath of the Lich King is, on one hand, an absolutely outstanding game. The journey to level 80 is an experience many gamers will not forget, with much of the history of Northrend to discover and many places to explore. On the other hand, Wrath is a game only for the players dedicated enough to reach level 70, and level 55 if you want to play a Death Knight. So for newcomers, they are somewhat alienated, as they need to put in the time to get to level 70 first, then head onto Northrend.
That being said though, for those willing to get past the first two games and head on into Northrend, they are in for a big treat, as Wrath of the Lich King is not only a solid expansion, but Blizzard's finest achievement and one which no gamer should miss out on.