If you're just shifting the tax burden, it's not a good thing, ESPECIALLY if it's race-based.
I agree, but that's not what Keyes has said. He has never given any indication that he would raise anyone else's taxes in order to offset the reductions given to descendents of slaves. Now, if he were a Democrat, I'd simply assume that this was a part of his "plan," but I have a hard time imagining Alan Keyes arguing for an increase in anyone's taxes.
Someone else on this thread just made another great point in support of his proposal: if it gets African Americans thinking in terms of personal economic empowerment and tax reductions, the Democrats wouldn't win another national election in our lifetimes.