It's really hard to see a completely symmetrical map that's played by people. I don't think the choice of the map was his worst fault. I think the biggest problem is that he didn't do a series of 1x1 matches. Although, by what he said, protoss should win because they'd just rush and fight each other. Or maybe not, because their armies could meet in the middle of the map or something. Anyhow he should do something like:

Terran x Terran

Terran x Zerg

Terran x Protoss

Zerg x Zerg

Zerg x Protoss

Protoss x Protoss

An extra resources version of Blood Bath, maybe? It also eliminates the randomness of expansions.