Recommender Leaving Poor Recommendation

A single average mark is not necessarily a deal-breaker, and in fact, scoring high on some categories and scoring average on one or two categories shows to the schools that the recommender is credible. It is the rare applicant who would score exceptional in all categories. Not that that isn't possible, because it is. But bare in mind that how recommenders score applicants is entirely relative to the peer group, industry competitiveness, functional competitiveness, etc. So the schools are aware that a perfect score given by a manager at A company in X industry does not carry the same weight at B company in Y industry. What's done is done, so let's try to shift focus to what you can do to control the situation. The bright side is that you know that perhaps your introversion (as per your self-assessment) may have impacted your recommender's score. So you can demonstrate through your interactions with the schools (networking, interviews) that you do have the interpersonal skills necessary to be successful in business school. I recommend prepping for your interviews with that in mind, with friends (ideally others who are well-versed in the application process) or admissions consultants who can help. If the rest of your application is strong (including, and especially your interview performance), you should still have a chance at overriding your recommender's assessment.