The question asked was, and I paraphrase, "will we be able to recognize if someone's aikido is better than O'Sensei's?" but everyone seemed to want to answer the question "will anyone ever be better than O'Sensei?".
If we are to take the question as asked it is easy to see that only those who have seen O'Sensei could make that decision and they would have to have been as knowledgeable when they saw O'Sensei as they are when they judge someone else against him ... an impossible circumstance unless the comparison took place in the same time frame, I'd say.
yours in aiki