I think it depends on your criteria. On a technical level to my way of thinking it's inevitable. Just look at sports today and you will see athletes who are not only faster, bigger and stronger than their earlier counterparts but because of advancements in technology and training techniques (weightlifting, diet, etc.) their ability is unquestionably better than those who came before them. I watch films of basketball in the 70's and it looks slow, the people seem small and it's almost a different game. In football, how many professional teams in the 70's had 300 pound lineman? How many teams today don't have them? Since the Olympics are going on as I write this, check out how many records are set or broken there and tell me people don't get better?
In regards to physical and technical skill, it's a no-brainer.
As to his spiritual development, that is a different matter. The O'Sensei's of today, whomever they turn out to be, won't look anything like O'Sensei. O'Sensei grew up in a time of war and I'm willing to bet that he never saw a computer. Today's O'Sensei's will be something completely new and won't be recognized as such because of this. They will be just as good or better though.