I just read an article that says Cowen and Company are saying SWTOR has the potential to ship 3million units at release. The article also informed that at this point in development that TOR has the same number of pre orders as cataclysm and Starcraft2 did at the same point in time on their development calendars. Thats saying something as the article didn't say anything about how SC2 and Cata didn't have any incentive for pre-ordering while SWTOR has a number of interesting items for each of their pre-order levels ranging from unique mounts to power crystals to an entire in game store for their overpriced drivel they call the "collectors edition" at 149.99 which I believe is sold out on a number of online retailers.
whether that says anything about it's popularity or not, i'll let you decide but while i don't particularly care for that giant darth malgus statue i'm sure there are a lot of hardcore SW fans that ordered it exclusively to add that to their doll...er "action figure" collection.
the article if you're interested-