When you look at the meters run in the Bundesliga, Kagawa is among the leaders, I think his stamina should be higher (90-92). In the Champions League qualifying round for instance, he was just behind Bender in meters run for Dortmund, who were among the hardest working teams in that stage of the tournament. He works extremely hard for the team and never stops moving. As an example of the inequity of the current stats, Ribery has higher stamina, but runs less in a match than Kagawa
Also, I think his passing accuracy could be higher, his pass completion rate (mid 80s) and the sheer number of chances he created for Dortmund this season were both quite high. Again, if we compare him to Ribery, kagawa is a more accurate short passer, but is currently rated lower. I would suggest an 83-84.
The final stat I would like to suggest changing is teamwork. Kagawa is a very effective pass and move player, his interplay with teammates is strong, fitting in very well with Dortmund's quick counterattacking movement. I would shift this to 85-86.
Overall, I just think he is a little underrated. He was probably Dortmund's most important attacking player in the second half of the season and they were clearly the best team in the league. More importantly, in the game now, he just will not affect a match in the way he should. Buzzing around, linking up with teammates, and playing strong through passes to teammates.