First, congratulations for Cilic for taking his first grand slam title and to Kei Nishikori for being a worthy opponent. Although the match was a little one sided let's not forget Nishikori beat Djokovic to get there. Not many people have that feather in their cap.
And then to address the question of whether Nishikori is the first Asian in a final the devil is in the detail. He is clearly the first man from Asia and one holding Asian nationality at the time to be in a final. Michael Chang was born in New Jersey to Taiwanese parents and is listed American so although of Asian descent, he wasn't actually from Asia or holding an Asian nationality at the time.
However for me this match seems to have been something of a turning point for the fans even if not the players. One area of development the Japan sports authorities has worked hard on over the years is to encourage the average fan (as opposed to the dedicated one) to support their team / player / athlete even when they're losing. Historically, if a team under-performed, the support simply dried up and interest moved on. England would regularly play to empty stadiums if people there took this approach!
So the most interesting aspect of the Nishikori defeat for me has not been the condemnation but the wide spread support in defeat. Losing is taboo in Japan with even Olympic athletes being forced to apologise to the nation if they didn't bring home a gold. However, so far on-line media is reflecting on the positives. He made it. He beat Djokovic. He's put his name firmly on the global map of athletes. And everyone seems to be saying "well done". Congratulations Cilic. Congratulations Nishikori. I wonder if this is a turning point. I really hope I don't need to delete this post in the coming days.