You should give it a try, Mirror's Edge deserves more love.
I waited over a year after DW7's release to try it because I wasn't too sure it would be enough of an improvement to warrant its purchase. The fact that they added Zhuge Dan and Deng Ai as playable characters (who are two of my favorites to play as in the Romance of the Three Kingdoms series) made me decide to buy it, and it was surprisingly good. I would recommend getting it, if you are a fan of the series. I think it's the best one yet. I haven't played Samurai Warriors, though, so I'm not really sure about that. I imagine that they would use improvements from one in the other.