Wellnow, I must say I have little use for Johnson, but that's not entirely fair. Either his criticism is valid or it is not, but either way the validity is not contingent upon the source.
I don't much care for how he approaches this as though it were put in front of a jury, and as though impeaching the credibility of people who support evolution was an appropriate tactic. It isn't - it's not a court of law here, but Johnson plays the lawyer's game with it by highlighting minor inconsistencies, and then claims total victory by simply extrapolating to assume that the whole thing is invalid. This fallacy is obvious to everyone but lawyers, I suppose.
Since he is also a church elder, it is like reading a critique of capitalism by someone in the Politburo.
Me thinks it's more intellectually credible to attack the arguments themselves than the formal education received by a person. Many great minds have made significant contributions to areas of thought in which they were not formally trained.