This doesn't scare me that much. I think Ariza is as good of an overall defender as Wallace (he may not put up the numbers, but he also doesn't have the lapses that Wallace has), and he is a better fit in general.
I really think Wallace is one of the most overrated players in the league right now, and he is not that much better than Tony Allen.
With that said, it is a realistic deal, and a great deal for Charlotte if they could pull it off.