"BioWare’s position is that this is somehow to limit the number of people for early access, but yeah, it doesn’t hold water. There’s no reason to limit supplies of digital products unless you seriously cannot facilitate all the players for it (which I doubt since the same game’s going to have to facilitate the same number of people at some point) or you want to increase demand."In fairness, marketing departments never met a controversy they didn't like, but there is a legitimate reason to limit pre-orders: ensuring that your server team knows how many servers to bring up on headstart launch day.
When the marketing department offers access to headstart day as a bonus for paid pre-orders, they create an expectation that pre-order customers will actually be able to access the servers on pre-order day. The problem is that headstart day is the one day in the entire life of the game when absolutely everyone online will be stuck in the same zone or handful of zones for newbies. For this reason, games that use the traditional server model routinely set lower population caps for that first day.
(Games where everyone logs into one server and then gets sorted out into as many copies of the newbie zone as are needed do not have this problem - I'm not sure which model SWTOR uses.)
Players who opted to pay in advance for the pre-order rather than waiting to see the reviews understandably feel that they are not receiving the access they paid for when they find themselves waiting for hours behind hundreds of players in the queue. Thus, word of mouth goes negative, and in many cases the game ends up with too many servers as the team adds more than they need in response.
In fact, I can think of one major, successful MMO launch that offered a paid headstart but that did not end up with the incorrect number of servers as a result - LOTRO. The reason was a deadline; players got to keep their characters from open beta, but only if they pre-ordered. Thus, Turbine had the luxury of knowing precisely how many servers they needed, and never had to merge a single server.
If EA is making a mistake here, it is probably that their cap is too high, assuming that there is a real cap to begin with and that they don't lift it altogether in response to the controversy.