There was also Sekac. There was an interview with him a couple of years ago where he admitted that he was not the best behave off the ice and wasn't really responding to the coach's advice.KK was as the talk after he left was that he didn't listen to his coaches and had an ego and was difficult or something along those lines. Galchenyuk was clearly off-ice issues though oddly enough both of them along with Tinordi were ones that there were rumors of their dads being an issue, say giving bad advice or telling them not to listen to their coaches but it's mostly hearsay.
The KK, Galchenyuk, Tinord, and Sekac cases lead me to believe there is something a little more than performance with Arber.