I have to agree with XavierJones.
XavierJones wrote:I say the third one is the best. So people will have to care about other groups too, not just their one.
With this it is more likely to get though the first round, if you had trouble in some matches. It also shows, how the two 2nd places could perform in the following matches, by comparing the matches they've played.
The first one is the middle way, which means it's acceptable, although it means that there are gonna be the risk of setting early winners. But if the matchmaking is based on raw pp it could go well.
With the second option to say is the worst. if it's only with 2 matches this would cause into enourmous pressure on the teams, and that every round literally decides about the end.
If it's with a rematch, it could be better, but still not good enough in comparison with option 1 and 3.