Dude's got some Eiichiro Oda snotty crying action going on 
While I was playing Onimusha 2 I was really struck by just how good the character models looked. The PS2 had tons of games with really well-animated characters but I felt Onimusha 2's were especially nice.
One thing that's really noticeable looking back is just how bad character models and animation generally were by comparison in Western games from the same time period with the exception of Half-Life 2. Devs didn't seem to give a shit and just went with stiff faces with basic mouth flaps even if the games were otherwise pushing the envelope graphically
It's very possible western devs didn't know how ti push the envelope when it came to character models and animations. A lot of this stuff does have a social element, devs do talk to eachother and share tips on how to improve in certain ways. I don't think it's a coincidence that western and japanese games had distinct styles, and I don't think it's fully creative intent. Technical teams need to have an understanding of how to get various systems to work well and it doesn't seem surprising that geographic and linguistic barriers can create differences.
One aspect that kind of hints at the potential cause being technical limitations: your western example requires at least a PC which is 3-5 times more powerful than a PS2. There's an xbox port, but I think the Half life 2 xbox port is considered a miracle comparable to the Doom SNES port.
On the other hand, you have games like the Ratchet and Clank and Jak & Daxter trilogies, all games by Western devs, all on the PS2 and all sporting expressive and lively characters. The difference is that those are cartoony platformers where having nice animation was most likely seen as crucial to the the intended style