Gunter never figured out how to use his size to his advantage. Al Harris wasn't fast, but he knew how to disrupt the timing of pass patterns in the first 5 yards. I never thought Gunter did.
Young Al ran a 4.45, Gunter 4.65. Older, slower Harris was also a master of the hold on every play strategy until they give up and stop calling it (similar to Seattle's CB's these days).