I definitely know what you mean, and I find it interesting too. I've found that the Asian actresses considered beautiful in the East don't really make much of an impression on Westerners for the most part. Of course, I'm probably generalizing alot and there are definitely many exceptions to the trend out there. Liu Wen is gorgeous in everything though!
I think a big part of it is that the faces Westerners find beautiful are skewed because of lack of exposure - whoever gets cast in Western movies or movies that make it big in Western theatres catches the interest of the public. The choices are so limited, and most of us are never introduced to Asia's more celebrated beauties.
For example, Zhang Ziyi getting cast as Sayuri in Memoirs of a Geisha? She doesn't even look remotely Japanese, and while not the worst choice, she certainly wasn't the best. But she had just come off of doing House of Flying Daggers and was already recognizable in the West for Crouching Tiger, Hidden Dragon. Gong Li was similarly far from the best choice because she's just not beautiful enough to play the imperialy gorgeous Hatsumomo, but she was relatively well known to Western audiences at that point so off they went with her (although she surprisingly pulled off the bitchy-haughtiness of Hatsumomo well because she is a good actress). The biggest travesty of that movie though was Michelle Yeoh as Mameha who was supposed to be elegant and beautiful. Michelle Yeoh is not even remotely pretty to my eyes (just mannish looking), but because of her status as a Bond girl and her role in Crouching Tiger, Hidden Dragon, again, they picked her over people who would have been way more appropriate.
On the other hand, most people wouldn't know who Lin Chi-ling was, even though she's one of Taiwan's biggest stars and drop-dead gorgeous to boot, because she hasn't been in anything that was well marketed over here.
I really love South Korean cinema, and have a soft spot for Wuxia films (in romantasized historical settings of course!) so I get annoyed by Hollywood taking literally every good movie out there and remaking it into a bad version (ogod, what they did to Old Boy) instead of just releasing the original here. (The one good adaptation I can think of is The Departed.) I also get sick of seeing the same Asian actors (Maggie Cheung, Ken Watanabe, Michelle Yeoh, Chow Yun-Fat, Maggie Q etc. over and over again - apparently because producers over here are unwilling to cast lesser known (to Westerners) actors and instead just reuse the same actors (without any regard for look/nationality/fit)).
There are some more deserving actors progressively being introduced to Western audiences (I think if they catch enough attention in their home markets, it finally causes Hollywood producers to take notice and cast them in stuff). I just read that Choi Min-sik is going to be starring in a new Hollywood blockbuster (Lucy), and Li Bingbing (who in my eyes, is one of the most beautiful Chinese actresses out there) will be in Transformers and reprising her role as Ada Wong in the next Resident Evil. Lee Byung-hun (I have a huge crush on him) was in G.I. Joe and is going to be in Terminator.
) I actually like Gong Li, despite how similar they look, but I think she's more classically beautiful and past the innocent doe-like phase that Asian culture looooves.
