Are Expansions Ruining World of Warcraft?

That seems to be the general consensus of what Games Radar is hearing, so they've decided to post a quick analysis of the most common complaints regarding World of Warcraft's expanded content.
So how could more content possibly be a bad thing? Well, most complaints we've heard seem to stem from the general way MMO expansions tend to funnel a majority of the population into its new areas, rendering old content obsolete. For example, The Burning Crusade provided players with a new level cap of 70, and introduced Outland, giving level 60-plus players a new but comparatively smaller set of zones to play in.

A mass exodus to Outland was partially balanced by the addition of two new races and classes for both Horde and Alliance players. Since both factions had brand new options for starting a new level one Paladin (for the Horde) or a Shaman (for the Alliance), there seemed to be a healthy amount of players to group with on the way to level 60 in (classic) WoW when TBC released.

With the introduction of the Wrath of the Lich King expansion, the argument that expansions actually reduce the size of World of Warcraft's world seems to hold a little more weight. By now, the novelty of rolling a Blood Elf Paladin for the Horde, or a Dranei Shaman for the Alliance had worn out. The mass migration to WotLK's new zones in Northrend had begun, making ghost towns out of major cities and hubs in (classic) and TBC zones.