> ... could we simply expand the board size a few spaces...
People occasionally experiment with other sizes, such as 21x21 boards. The size of the board has a strong impact on the nature of the game, though.
The obvious change is that larger boards take longer to complete, putting humans at a disadvantage if fatigue comes into play. Less obvious is that 21x21 changes the value of tradition strategies. It is generally considered equivalent to play for board-edge territory as for central influence on a 19x19 board, but on 21x21 playing for the easily-defended outer regions is too small. The value of the center means that it's more valuable to play for central influence instead.
To answer your question in short: it's possible, but expanding the board size could make the game unfamiliar and decrease the effective ranking of pros.
People occasionally experiment with other sizes, such as 21x21 boards. The size of the board has a strong impact on the nature of the game, though.
The obvious change is that larger boards take longer to complete, putting humans at a disadvantage if fatigue comes into play. Less obvious is that 21x21 changes the value of tradition strategies. It is generally considered equivalent to play for board-edge territory as for central influence on a 19x19 board, but on 21x21 playing for the easily-defended outer regions is too small. The value of the center means that it's more valuable to play for central influence instead.
To answer your question in short: it's possible, but expanding the board size could make the game unfamiliar and decrease the effective ranking of pros.