The current best player is Maru not Serral, he won WESG and the two GSL's so far. The races don't have problems, and the 12 worker start simplified openings which helps balance.
Serral beat all the top Korean players in his wins including Innovation and Stats, Maru in the same recent tournament got destroyed by someone Serral swatted.
No 12 worker star broke the game it's is the main cause of the erratic early game the game has and I can highlight why, 12 workers gives players near full mineral saturation the result is builds that were never intended to be viable now exist and example is how Protoss can expand as fast as Zerg now while being able to pressure your natural with an array of cheeses and pushes. This was not possible before because the 6 worker start meant taking a gas impacted expanding and a players economy this what everyone on BNet, TL and Reddit SC are now realising and bringing up because you can't balance a game where the flawed econ undermines its fundamentals.