His main mistake was encouraging the Kurds and Shi'ites to revolt and then allowing the revolt to be crushed.
Political will of Iraqi generals notwithstanding, Bush more likely underestimated the strength of the remaining Iraqi forces - the forces that Schwarzkopf et al were told to allow passage on their way to quash any uprising.
He let Turkey's interests intervene in the North and likely got scared of an Iran-friendly Shi'ite faction to the South.
Of course we don't have those worries today, because we are going to install democracy. and if those factions want their own democracies, well, tough noogies.

Cheers,
Tony