If all battles start at the same time, wouldn't it be hard to keep track of for the spectators/GMs who host this event?
IMO, to refine this idea, I would suggest a gladiator style where 40 or so players enter a map that is free-for-all and the top 8 players (<-maybe more players) who get the most points will advance to the semi-finals where there will be a 1v1 match and your opponent is chosen at random. To get a point in the 40 players FFA round, you get kills. For every one kill you get, you will be rewarded with five points. During the semi-final rounds, you can spend your points to get buffs. Certain buffs will cost a certain amount of points. During the final round you may also use your points for buffs so players have to spend their points wisely in the semi-final rounds. Semi-final rounds will be a best of 2/3. The remaining 4 players will advance to the final round where there will be a best of 3/5 round. The two remaining players will face it out in the championship match which will be a best of 3/5 round as well.
Idk I think that this idea would have less flaws and keep it better organized for whoever is hosting the event. Also it will force the cheesy classes to actually fight during the 1st round and not just run and spam seeds.
So it would look something like this after the 40 player FFA round if you don't get what i'm saying.