He had no regard for his troops' lives - something like 80% of his soldiers that went with him died, and he conscripted new guys everywhere he went. So he'd con

He had no regard for his troops' lives - something like 80% of his soldiers that went with him died, and he conscripted new guys everywhere he went. So he'd conscript, shock attack losing a lot of guys, then conscript from the newly defeated, and repeat. He did make advances in strategy and technology too - I believe his major military innovation was actually much longer spears than opponents, and he moved fast enough that that technology wasn't diffused and adapted. He also executed, assassinated, or otherwise brutalized his own supporters fairly often when it would advance a goal of his. Alexander's romanticized in the west, but he didn't have much respect for the lives of his soldiers and people.