It was pretty pre-detemined (at least in the matches vs Mana. The best pros can react very fast to unusual strategies (cheese), or change their strategy if the situation calls for it (eg: terran all-ins).
I agree with the sentiment of disappointment of having to make a "league" with specialised AIs. It seems to be lacking a high level reasoning and executive module, and the league acts as a crutch. The league idea still super impressive and clever, but human players do not go around in gangs where only one of them takes a seat for each match.
