He's 22 now right? Should mean he could still improve. 10 goals and 9 assists in that team as you say sounds rather good imo. The nine yellow cards doesn't bother me, shows he's aggressive and not someone who doesn't dare to tackle or win the ball back. No red cards accordingly so he hasn't done anything "stupid".
yes he turned 22 at the end of may.
the yellow cards don´t bother me as well. i just wanted to figure out how many games he missed due to injuries

. i´ve never seen him doing anything stupid as well and furthermore he doesn´t strike me like a player who gives up easily when things aren´t going his way (which is unfortunately rather common for that kind of player).
@hummels:
i think our chances aren´t that bad. he doesn´t look like a player who would put money over solid surroundings and maybe some history. so i´m rather confident he might put a club like juve over mancity, psg etc.. furthermore i don´t think that there will be too much competition from clubs like barca o real because he wasn´t really able to show much of his talent in europe.
last but not least i hope he tells bayern to fuck off. they sold him for almost nothing when he was going through a rough time and didn´t show any faith whatsoever... show some character mats ^^
man i would kill for a defence with mats, chiellini and licht in it. doesn´t matter whos the LB/2nd CB. even giants like ibra would cry themselves to bed when they had to face such a physical defence on the next day

. ibra isn´t a great example though because i guess he would even cry if chiellini would face the entire milan side on his own
//edit: one more thing about hummels:
imo dortmund might be willing to sell him even though he is one of their key players. their financial situation still isn´t that great although they did very, very well to improve it quite a bit. furthermore he is one of the few players they would be able to replace quite well with a player they already have because santana showed to be an excellent CB.