It was so new in fact that our textbook was still the old one so we only partially used it. I can attest that at least in my experience, Pope John XXIII and Vatican II had a profound impact on many of the young priests at our school. My freshman religion teacher hadn't yet even been ordained but was the following year. Because of the openness advocated in Vatican II, students had many more heartfelt talks with priests than in the prior years and many of those young priests opened up to us about their feelings and even some doubts. Even though I'm not much engaged in the church these days, I have fond memories of those times. I had heard that several of the young priests from that time left the priesthood eventually.
I bring this up because Pope Francis was a young priest during that time. From his current behavior I would say the Pope John XXIII had a big impact on him. Following Pope Pious XII, who would never be described as warm, Pope John XXIII was a breath of fresh air. He wanted the laity involved which for an altar boy meant having to really remember your Latin as the people were expected to say it along with you and that meant you could no longer quickly mumble it. To Pope John XXIII, all people were important not just Catholics. He believed the Pope should embody Christ in word and action, not just head a bureaucracy and set down a bunch of rules. It appears to me that Pope Francis is following that same philosophy. Whether this translates into changes to actual church dogma is another story but I would say that, as we have already seen, strict adherence to the rules is not the emphasis. Pope Francis is more concerned with the person. If Jesus was willing to forgive who is the Pope to not follow in Jesus' footsteps.
In grade school, religion classes were all about learning the Baltimore Catechism. Each class we would be given a rule and then spend the rest of the class, or so it seemed, thinking up exceptions. I'm always surprised more Catholics aren't lawyers. Anyway, the Catholic Church is still a big institution and bureaucracy. Like a big ship it turns slowly. Frankly, Pope Francis' impact will be seen in how long he lives. Pope John XXIII papacy was fairly short and he didn't appoint many cardinals. Although Pope Francis is 77, with modern medicine his papacy may last a long time and he may have a lasting impact on the church. As someone who thinks none of the subsequent popes have measured up to Pope John XXIII, Pope Francis is the first to make me believe that he will.