Well the fundamental premise of the Great Leap Forward was flawed. You cannot substitute expertise with large numbers. Kicking out the Soviet experts, who might've helped implement the plans more successfully and/or draw up more realistic plans, didn't help. But ultimately it was never going to work because it was based on a flawed understanding of agriculture, industry, and logistics.
But the thing that led the GLF to kill millions of people wasn't the plan itself. In a more accountable system, the government would soon realize how much a disaster the program was becoming and would bring it to a halt. But instead what you had were thousands of party cadres systematically cooking the books and lying about the progress happening in their village, county, province, etc. both out of a sense of fear (they didn't want to lose their job) and self-promotion (they wanted to acquire prestige and get promoted within the party). There was no oversight, no system of accountability, and no real way to correct the situation quickly even when it became apparent that stuff was going wrong. Instead you had party leadership looking at the (falsified) reports coming in and thinking that the Great Leap Forward was a great success! So they would then respond by raising quotas even higher, forcing the party cadres to produce more and more even as they had actually failed to meet the earlier quota.
Of course the ironic thing is that if the GLF is less of a disaster, it will only empower Mao further. IOTL the failure of the GLF seriously discredited Mao within party leadership and allowed for his rivals to take effective control of the party from him, a struggle which even then lasted over a decade and resulted in the Great Proletarian Cultural Revolution. If Mao is never discredited so thoroughly, he will continue to effectively be able to rule by decree, and you can sure expect further Great Leaps Forward or worse.
