The way the did the expansion made no sense, it's like they didn't even want to expand. They were essentially punishing the expansion teams for joining the league!
The way I see it is that there were a multitude of factors:
1) In some sense, it's a very exclusive club of people allowing fresh new faces to join their fraternity. There is always going to be some level of resistance from the established club, especially since the new faces are potential competitors down the road. However, I'm sure the initial pill was easier to swallow since a third round was added to the playoffs, which brings me to the second point.
2) In some ways, in terms of making and playing in the playoffs, the East Division was basically the O6 group of teams renamed. The winner of that was basically guaranteed to be the Cup winners, with the added third round a formality for the winner of the East Division (plus extra money for the winning team due to more home games).
3) In the worst case scenario (which obviously didn't come to pass), if every expansion team flopped, it would have been a failed experiment with no loss of integrity for the Cup winner. It would have sucked for the new owners, but the old guard would have made a few extra bucks and gone on with their business. Of course, the worst case scenario must have been seen as highly unlikely because...
4) Two-thirds of the expansion teams would make the playoffs, and one of the would be able to challenge for the Cup in their very first season. (Or as it turned out in reality, first three seasons.) Every team in the expansion division would get a shot in the playoffs due to parity in that conference. You could argue that none of those teams would actually stand a chance for a while (hence St. Louis being knocked from its three straight Cup runs the moment Chicago joined their division), but there's nothing that builds a fanbase better than winning playoff rounds off the bat (even if it's in the weaker division).
But back on topic: this is one awesome game.
