After having watched all the tournament splits for League of Legends, CS:GO, Guild Wars 2, and other games, I'm not to sure Overwatch will be as big. Sure Overwatch is fun to play but the different game modes they do have don't seem to be that entertaining too watch. Given this can change based on the announcer and maybe if they add different modes but thus far its based on pushing the payload to the objective in a best of 3 match. Each match will have a best of 3 in which the team that completes (if both complete the objective whichever team does it the fastest) will win. Overwatch doesn't seem like speed should be what the match winnings should be based on, but thats my two cents.