It was an iconic game in the MMO field for many years. World of Warcraft showed us how the genre should be done, and done well. Blizzard put epic amounts of work into building, supporting, and maintaining the game, and it kept millions of players around for many years.
I myself started during the Burning Crusade, played all through Wrath of the Lich King (got to kill Arthas too, back when it was still hard), and then played up to the Firelands in Cataclysm. But my time in that epic world is now passed, and as I look upon the scape that is the field of MMOs I see the sun is setting on that great cyber empire. Like so many others that have gone before, it has had its time in the sun. But the world has been waiting for a successor for some time now, eagerly looking for something new to take its place. People thought Rift would do that, but it failed. People now say Star Wars: TOR will do it. We will have to wait and see.
But this is not necessarily a bad thing. Like the British Empire that once spanned the world so that 'the sun never set' on its lands, so it's fall brought about a new era of independence and fresh starts. World of Warcraft has been an awesome game, and it changed the landscape of MMOs forever. But now as it declines there is an opportunity for fresh starts, for new companies to come along and build their own games off what Blizzard taught us with WoW. I see Bioware as leading the pack with TOR, but they are certainly not alone. New things are out there, on the horizon. Let us embrace what is to come.