The applicant did not devote sufficient time to the application - Applications containing mistakes are screened out and rejected during this phase
Did not brainstorm well enough in answering the reason for why MBA? - Most applicants don't do the brainstorming and end up with errors in their application, which get them dinged.
Applicants did not bring out the right leadership examples - Business schools value leadership because it demonstrates an applicant's ability to direct a team's efforts toward a single objective.
Failed to highlight the strengths properly - Adcoms are people, and like all people, they enjoy hearing a good story, especially one that demonstrates your strength.
Generic post-MBA goals: Management consultant or Product Management - Being overly generic will almost certainly result in your application being dinged.