Based on the "new audio", we don't know what happened. Brown could have easily taunted and stepped toward Wilson or either after turning. The one that matters isn't really the taunting though, but rather did he make any move that could be considered threatening. We don't know how Brown would have reacted. There have been people who have charged police after getting shot at, taunted police, threatened police. We do not know Brown's mindset at that time. Not all people make sense.
As for him committing homicide in front of several witnesses that say he killed a surrendering man, that is what we are trying to find out. He could have been justified in believing that Brown was a threat. At least one person on that video of what was going on right after Brown was shot did say that he saw Brown moving towards Wilson. Is that verified? No clue. But it is there.
Michael Brown shooting recording casts doubt on claims he surrendered to Darren Wilson | Mail Online
If this is real, then it could be a witness statement of events. In fact, given the time it would have occurred, it could be more believable than some of the other witness statements, because there is little time for false memories to set in when more information comes out. Now, it could also be just this guy didn't really get a good view.
There were problems before, but we don't have any evidence that there were complaints against Wilson personally. In fact, there should have been some if he was a problem.
Plus, there is also no evidence that this was racially motivated. Just because Brown was black and Wilson was White does not mean that Wilson only shot at Brown because he was black. You cannot prove racial motivation here. Not with the information we have.