Well, he is a head of state. Although the Pope wasn't seriously injured, a nearby 87-year-old Cardinal broke his hip and had to have some immediate surgery. Susanna Maiolo apparently has a history of mental problems, so it's doubtful the Vatican will prosecute her.
When the Pope visited my campus last year, security was pretty tight. We had to be kept at a certain distance, the Secret Service was all over the place, etc. Overall it was much more security-minded than when JPII visited a few decades ago, as I understand it. It's a shame that in this day and age taking part in public gatherings increasingly necessitates stricter security.