It depends on your definition of Hero.
Alexander was...
-Ruthless
-Power hungry
-Shallow
-Narcissistic
He..
-Killed hundreds of thousands of people. Murdering or Executing them.
-Was the cause of many soldiers and civilian deaths.
-Mistreated his soldiers
-Burned cities to the ground
-Sold and forced many women and children into slavery as he massacred the men of military age