For the most junior positions (such as business analyst that 20 years ago was for undergrads directly out of school) they will be looking 50% to i), 25% to ii) and 25% to iii). However, you can not be genius in i) and have a lousy score on either of the other two.
A junior position is about doing (so hard skills are a must), but they need to see career progression possibilities. So a person that comes across as not able to communicate in a structured way, or without cultural fit will be discarded.
Typical pitfall of an engineer: trying to show off coming up with a very complicated solution for the case interview with endless loops. Mckinsey is looking for the opposite: the beautiful simplicity of concepts boiled down to two-three key insights.
Former Summer Business Analyst at McKinsey & Company
about 2 years ago
Leadership, ability to drive impact, take initiative, work well in teams and solve conflict, come up with innovative ideas, passion for an industry and/or consulting itself. Also don't forget to show case your interests and personality. I hit it off with a partner by talking about the time I did the "Krispy Kreme challenge" and when I dabbled in competitive eating.