I don't really agree with you. What made BroodWar balanced was meta development and map creation that took a long while. Every race had some things that could seem imbalanced and outright crazy. Reaver single scarab killing 20 marines or your entire SCV line, storm nearly killing everything. Plague reducing all army to 1HP, lurkers that wreck havoc.

And yet, no single race dominated over all of history. There were times when Terran we're most dominant. Then came Savior and rest of zergs who were suddenly winning everything. Until Bisu's revolution that is...

Point being every style had a counter, you just had to make it work (with builds and pure skill).