The main issue is stracraft is pretty complex and if the computer is predictable, a human can just exploit that for easy victory. (always 6 pooling for example)
I guess that bots' micromanagement will become superior to humans, if it isn't already. A bot won't have any problem coordinating three or four battles at the same time. For humans it's quite hard to fight a multi-front war given StarCraft's UI.
Even the Insane AI in SC2 (which gets cheat advantage to minerals and gas) can be beaten 1v3 with just a 10 population protoss.
AI vs humans is rarely the standard 'Starcraft game' so much as its a puzzle game. The winning thing vs 3 insane AIs in SC2 was merely to forge-rush. Once you knew how, you could never lose to that AI again.
I'm sure the same is true of these AIs.