Note that some of the "3-0 fests" have been in favor of the lower seed, so that rather speaks in favour of having more players.There have been a few interesting results, but on the whole it's been a bit of a 3-0 fest. Not sure an S-tier tourney needs 32 players. 24 perhaps?
I think the main reason for it is the Arabia only format. In many tourneys, if you are having a bad day and the opponent has a good day, you can try to get into the match by forcing your playstyle onto your opponent. But with no home maps to prepare specific strats for, just one map that is very well-known to everyone, you don't have that option. If you are having a worse day, there are only very few things you can do to break your opponent's rhythm.