I think this match showed where NicK needs to work. In many ways its a simple matter of maturity. Actually, I'm reminded of Louis CK's bit on 20-year olds (see video at bottom - some language).
Clearly he has the talent and weapons to compete with anyone. In fact, Kyrgios could be the guy that is able to take Novak down--IF he matures. That is a big "if." It might take a year or two of hard-knocks for him to lose the chip on his shoulder, or at least transform and focus it into drive and passion for winning. I think the potential is there, though.
Kei played a great match - it really showed how when he's on, he's a tough guy to beat. He's sort of a different variation of David Ferrer: he won't overwhelm you, but where Ferrer can win the war of attrition through wearing you down with his incredible tenacity and fitness, Kei has some weapons to strike when the opportunity arises. If he stays healthy, Kei could be a top 10 guy for another five years...although probably never top 3.
https://www.youtube.com/watch?v=Gv8-Xtll3l8