Are Shakespeare's views of human nature and interaction in Romeo and Juliet still relevant today?
Absolutely! Shakespeare shows us so much about human nature that still remains true today. He seems to have understood something vital about violence. The feud between the Capulets and the Montagues, for example, is completely futile. No one seems to even remember exactly why the families are at odds, and the younger generation only seems to fight over some vague notion of family honor. Their violence and hate has unintended effects, wounding their own family as much as it hurts their enemy's. Shakespeare shows, then, both the futility and the uncontrollable damage caused by hate.
Further, Shakespeare completely identifies the rash and impulsive intensity felt by young people, and he doesn't present it as something that needs to be stifled so much as understood. Whether or not the reader thinks that Romeo and Juliet are truly in love, whether they can truly be in love, is irrelevant. They believe that they are and if their parents, Juliet's especially, were more respectful of their feelings, then it seems likely that the couple never would have ended so tragically. Communication between parents and their adolescent children was apparently pretty difficult during Shakespeare's time, just as it is in ours, and he makes a compelling case for treating teenagers and their feelings with empathy and compassion rather than ridicule and judgment.