Doug Creutz from analyst group Cowen and Company estimates that subscriptions for Star Wars: The Old Republic will drop more than 25% from February of this year to the end of the current fiscal year in March 2013. For exact numbers, that's 1.7 million to 1.25 million subscribers.
Creutz bases his speculation on server statistics based on TorStatus.net and some educated guesswork:
We believe that the apparent decline in subscribers is most likely due to a lack of 'end-game' content for the title, meaning that players who hit the level cap have few compelling options in terms of ongoing gameplay. While the game got off to a good start, the relatively light amount of end-game content does appear to be taking a toll.
We believe EA is attempting to address the end-game content issue, including a recent major game update, but momentum appears to have stalled and we believe it is prudent to adopt a more conservative forecast on subscribers at this time.
While Creutz still safely estimates that Electronic Arts will do fine—and they will—but this doesn't bode well for the new IP.