OFB-11!

If someone wants to withdraw, let them. It's better than having meaningless games in the following rounds. Just don't make a huge deal out of it. Send a private message or an instant message saying, "Please withdraw me from the tournament," and that's it.

I think such a tournament should initially be held using a Swiss-system format with elimination rounds.

Of course, it's possible, but there are people who just want to play, preferably against strong opponents. Let them play.

As soon as the number of players in the tournament corresponds to the number of qualifying spots, the tournament ends immediately.

You never know how many players will be needed. Someone might drop out, so it's reasonable to finish the tournament properly so that you don't have to rush to decide who to include later.

But how can it be more upsetting than it already is? I've already been eliminated and didn't qualify for the finals.

It will be upsetting for those who still have a chance but will lose it in the last round. Winning 7 out of 9 games is not as easy as it seems.