Chicago Blackhawks or Atlanta Braves as examples in name only I think are potentially positive (debate could be was it intended to be?) and not derogatory, other aspects may be bad (symbols, crowd chants, etc.). Maybe with some modification of other aspects these names can be a very positive image and a history teaching tool. But maybe if I was a Sauk I may not like them using the name Blackhawk, or maybe I would.... that I obviosuly cannot know on my own as I am not Sauk. The voice and opinion of the people "targeted" (for lack of a better term) is an important part of the debate.
I am actually curious what natives think of those names. On the surface, calling your team blackhawks and braves may seem benign. But they are still names of tribes that were conquored by the white man, and now the white man is using those names to sell sports.