The ones with flaws that led to them getting beat a lot we don't hear of. Vito Antuofermo cut easily, but usually over came it. Foreman had fatigue issue, but ko'd everyone quick, till Ali and Young fights.
his footwork improved and yes footwork is a part of defence, he does pull back but he uses one of his outstretched arms to control the opponents direction, dirty tactics, but its a fight, most greats use dirty tactics.
You didn't ask about FIXING a flaw, just overcoming it, which Wlad did by changing other tactics. Be more specific next time!