successful in what sense? are you planning on selling tickets or something like that to cover the "prizes"? or are you going to pay them out of your own pocket? if it is the later then yes it will be very successful but if you plan on selling tickets or raising funds or something like that, I don't think you can get that many people interested in it enough to pay you! even with escrow since most of these games and tournaments are free. and you can always join online and play for free too.
it is an interesting idea though. you can use an escrow with multiple signatures and since everything will be on the blockchain the prizes will be transparent.