Buckner is not a defensive stopper.
He earned the reputation as a defensive stopper while in Dallas, when they were all attack no defense. He was the only one who played any spec of defense, and he could shoot the 3 a little, labeling him a "defensive stopper".
He's not a bad player, but he won't "neutralize" Wade. I doubt he can even keep up with Wade. But he would be a good backup, just don't expect him to lock-up anyone