I hate to say it, but just because there is a pattern in expansions DOESNT mean that they HAVE to follow it. I think that they wont be going to 4 for a while. The reason that they most likely only did 2 for RCT2 is because both were REALLY crappy. They were basically JUST scenery expansions. I think that there'll be a few more expansions, at lest untill this one starts to die like RCT2 did expansion wise. So far, RCT3 has been going much better than 2, in the way of expansoins. Expect a few more for RCT3.