Hmmm...I consider this topic to be an "Apples vs. Oranges" debate.
I truly believe that Western music is more creative/influential because not only has Western music (both mainstream and indie) influenced the world with its sound, it set the bar for how music should be made, performed, promoted, etc. From eccentric artists like Bjork to and mainstream artist like Kanye West, (
YES! Kanye West is EXTREMELY artistic, every album I heard from him is amazing and there is NOTHING you can say to change my mind!! 
) I feel an erray of emotions I can't get from other Asian artists. However, I feel that Asian music has a set theme for their overall music.
To make it easier, when you think of Asiann music what comes to mind? Maybe something exotic like Arabian music for bellydancing or something from a far eastern mountain with fog and foreign strings with drumming beats? I'm not too good with describing it but I hope you get the gist! And when you think of Eastern music, a lot of fancy and exotic colors, clothing, and pretty looking things come to mind. But with Western music, it's more mixed and somewhat muddled because of the mixing cultures and races.
Now I'm going to lie and say Western music today is as strong as it was 10 years ago (after 2006 MAINSTREAM music went completely downhill) but it still has that influence. And here's my reasons to back up my claim:
1.) The K-Pop Wave/Hallyu wave is heavily influenced ranging from American R&B/Hip-Hop/Electronica/Pop. The only difference is that they just made their music slightly cleaner, wore bright colored outfits, cute "perfect" faces, and their look is more conventional compared to their American counterparts.
Ex.
Wonder Girls- Nobody: HUGE hit in 2008. Has African-American influences ranging from the Motown inspired PV, the Dreamgirls from rags to riches theme, Yoobin's voice in general has a tough-image sound etc.
2NE1- Their sound- CL raps like Da Brat, Minzy mainly freestyles to Hip-Hop music, Bom sings like American R&B artists, and Dara sings/raps have a light pop influence
Big Bang- Went from straight, semi-hardcore Hip-Hop/Rap/R&B to Pitbull-esque Pop and electronic music.
2.) Japan during mid 90s-early 00s, was like watching American MTV, VH1, and BET. It felt to me everytime you would see an American artist come out with a new song or video, a Japanese artist would make a copy. I can't think out the top of my head but Namie, Koda Kumi, Utada, and Ayu were the first ones to stick out.
Overall, what I'm trying to say is that I think Western music is more creative because Asian music set the same pattern for decades and if an artist decided to do something different it would more than likely be Western influenced.