Well compared to the fact that the PS2 versions of 2007, 2008, and 2009 all outsold the next gen copies it doesn't surprise me any. Also its probably becuase the PS2 is still holding its own in sales against PS3, Wii, and 360.
I'm VERY happy they decided to put this on the PS2. I'm wary of it being another let down, but as I'm easy to please (My favorite games of all times are button-mashers like DBZ Tenkaichi 3, Dynasty/Samurai warriors series.), I'm sure I'll be able to have fun with it.
The only thing that would make me happier would be the news that Dynasty Warriors 6: Empires will be ported to the PS2. But.... I'm not holding my breath on that. So for right now, YAY SvR, BOO OTHER GAMES! (Unless you bow to my wishes, in which case I will spend my sweet, sweet dollars on you for more mind-numbing hours of brain-rotting entertainment and fanboyism.) --- I'll blow you away! In a minute! As soon as I remember how to do this move. I think I press R2 and then... dang.