While I think that there is a lot of value in considering that their record of building and operating the business deserves to garner a great deal of trust, one of the more common ways very smart people get into trouble is by believing that expertise in one field translates into another. They have certainly hired a number of excellent people over the years, and have had a few who did not work out (e.g. Sokol).

I'm certainly willing to entertain a high level or trust in the decision makers at Berk, but hiring someone with a long track record of excellence is different than projecting future success on someone who has not already done so. Predictions about the future are even harder without evidence from the past. I think that being uncomfortable about the appearance of nepotism where there has not been public demonstration of exceptional competence is a valid reason to be concerned. There is certainly some scope to extend trust in their decisions, but that doesn't mean that we should give over any concerns at all - but perhaps keep and eye on it and see how it looks as it plays out, and be ready to speak up if problems arise.