For his first year in the NHL, Brunner's offensive talent was very good, and he was even a big offensive threat in the playoffs. That's all true, and that's what you see if you look at his stats. However, if you watched him every game of the season there are other noteworthy details.
First of all, he came straight from playing pro in Europe to an NHL that had been sitting longer than usual. When Brunner started, he was in peak season form while his NHL peers were still trying to shake the dust off. It was during that early part of the season that Brunner did almost all of his goal scoring. When the rest of the NHL got into its rhythm, it also started playing Brunner harder defensively. As a result of those two developments, Brunner went into a tremendous drought.
When Brunner started having trouble scoring, the Wings stuck with him at first. But it was a shortened season and the Wings have other young players who deserve a shot. Eventually, they demoted Brunner. Brunner wasn't demoted for very long before he was given a second chance. So, if that's where Brunner's problems with the Wings come from, then he has ego problems. Even after given a second chance, he didn't really respond well.
The last point to make about Brunner's play is that he is a one-trick-pony. A lot of European players aren't very physical players; that's not what I mean. What I mean is that Brunner was a liability defensively. He was absolutely brutal in his own end.
Getting rid of a bad attitude and giving another young player a shot might be a good thing.