It is? In a population of less than 25,000 - this would come out to a fraction of a person. So perhaps historically nobody ever got this 0.004% mutation in the first place and it certainly would not have been even a possibility in the fitness landscape as it was starting very far away from what would be “efficient” hundreds of millions of years later.
Let me try to summarize what you are saying and let me know if I’m misunderstanding you. Are you trying to argue that natural processes would have selected for a more efficient design by now and thus this nerve is better evidence of a non-common descent/supernatural creation type of model? Since it has not it doesn’t make sense to argue that this is ‘bad design?’
I personally don’t like the argument from “bad design” but rather am trying to focus on “evidence of common descent” that does explain the pattern of the laryngeal nerve quite well.