Exactly what I was going to write.
Remember Matt Murton? He had more hits in one season in Japan than Ichiro ever did in Ichiro's 7 seasons in Japan.
American Leron Lee (who?) is Japan's all-time career batting average leader (.320) among players who played at least ten seasons. (1977-1987).
American Randy Bass (who?) has the season record for batting average, .389 in 1985, and hit 54 homers the previous season.
American Robert Rose (who?) had the second most rbi ever in a season, 155 in 1999.
Imagine if Harper, Pujols, Bautista, Cabrera, Davis, Ortiz or any great slugger played in Japan at their peak. They'd hit .400 with 70-80 homers a season.
On the flip side, it shows how incredible Ichiro is that he could be such a great hitter against MLB pitchers.
I am glad you put that "flip side" part in. Ichiro is extremely talented and deserves praise for his individual personal milestone. To me it is not a record by any means, but give the man his due, as it is quite an accomplishment.
Also, I remember Randy Bass!