EVE doesn't exactly have a firm number 2 position...there are a couple titles that are colse enough to surpass it in the US market. Counting Aion out is foolish.

From what I've seen of Aion, I think it has the mass-market apeal that WoW does (some will be turned off by the anime-esque styling, but many WoW geeks like anime...). It also looks good, and runs well on older systems (not quite as old as WoW, but it does a very good job). The marketing push is also definately there as well, and they have a lot of hype going for it. Hype will often kill a MMO out the gate that isn't ready, but with Aion having been out in Korea nearly a year, it is very polished and feels like a retail product already, much moreso than any other MMO I have tried in recent years.

Remember games like Warhammer Online actually sold 800k copies, but they didn't stick around because the game was ultimately repetitive and unstable in high-end PvP. If Asia is any indicator, Aion is not a poor game. The only question is whether or not it will be as well recieved in the western market...and I think it will.