Wallace had not done the same. The command at Stirling was Andrew de Moray, while Wallace had not taken the time to train his men in mobility like de Bruce did.

And the schiltron wasn't used at Stirling. Stirling was a simply rushing against a cut off enemy at a bottleneck.

Also the only threat to the Scots at Bannockburn were the longbowmen again, but due to impatient kights, King Edward's lack of control, and his own stupidity these were not a factor.