When I first saw the screenshots for this game, I was still half asleep, and they didn't really click with me.  I DID know that I liked what I saw though.  Now that I am awake, I realize a little more about it.  The Shinsen Gumi were very much a part of the Rurouni Kenshin anime, and had a big part in the OVAs that I love so much.
I must say that if I owned a PS2, I would SO be importing this game when it was released.  There are very few PS2 games that I would actually buy, but this one is definately a keeper in my books from 
what I see of it.
I suppose that there are now about 4 or 5 PS2 games that I KNOW I would own if I had a PS2.