Earlier this week, the highly-anticipated Aion finally launched in North America and in Europe today. Developed by NCSoft, Aion's release was just as successful as many predicted; selling 450,000 pre-order copies, making it the best-selling MMO of 2009. Much of that success is probably because Aion isn't technically a brand-new MMO; it has a proven record of accomplishment in Asia, where it's had enough time to be polished and primed for its Western release. For more information, check out our Aion preview, which we published earlier this summer.
As a long-time World of Warcraft player, I was more interested in the new MMO's playability from that specific standpoint than anything else. For example, many players found a steep learning curve in the transition from WoW to an MMO like Champions Online. If WoW is your earliest or "primary" MMO, it's probably the benchmark you compare most new games to. As a hardcore WoW player, will Aion's gameplay come naturally to you? Regardless of its merit, what familiarities are you guaranteed to find in Aion, and to what extent?