Although I think there's no chance the Cardinals would go after him, it would be a good move in my opinion. He's a very good outfielder with a good bat, and although it is hard to say how Japanese players will translate to the MLB, several position players recently have done well.
I believe he doesn't need to go through the posting process either, so that's much less money the team would have to spend. Plus, a star Japanese player on the team (So Taguchi was never much of a star in Japan...) would bring in a lot of revenue for the Cardinals.
I think it makes a lot of sense to go after Fukudome this offseason. However, other than Taguchi who was basically off the radar, the Cardinals have never seemed very active going after international players. I always thought guys like Iguchi and Iwamura would have filled holes for this team. They didn't sign for exorbitant amounts of money either, and yet, the Cards never seem to even show any interest at all.