Back before the internet and so many Disney fan websites, a soft opening was truely a soft opening. A few days or weeks before the announced opening date of a new attraction, Disney would open the ride ride and not advertise it. People who happened to be at the park those days got to ride it before the general masses.
However, with the explosion of the Disney websites, there are no more "secret" soft openings. Once a ride is going to be opened (even if before Disney's official "opening day" for the ride) the secret is out and thousands of people show up to ride it. Somebody on anther thread spoke about how long the line was for Space Mt on it's "soft opening" date. People came to the park just to ride that one ride because they knew it was to be a soft opening date. I'm sure you who live closer to DL can tell other similar stories about other rides.
So, does the "soft opening" still exist? I'm not asking of Disney still does them, but rather, how are they different then an "official opening"? (but it sounds like they might not having a soft opening for the PotC.